IC-NRLF 


1 


THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 


PRESENTED  BY 

PROF.  CHARLES  A.  KOFOID  AND 
MRS.  PRUDENCE  W.  KOFOID 


LIBRARY 

OF  INSPIRATION -AND 

•  ACHIEVEMENT 

EDWARD  EVERETT  HALE 

EDITOR-IN-CHIEF 


I 
II 
III 


SVCCESS  AND  HOW  TO  WllN  IT 

CHOOSING  A  CAREER 


HEALTH  AND  ATHLETICS 
iv  READING  AND  HOME  STVDY 
v  MAKING  HOME-LIFE  ATTRACTIVE 
vi.  MEN  OF  ACHIEVEMENT -BIOGRAPHIES 
vu.  MEN  OF  ACHIEVEMENT-  INVENTORS  &  SCIENTISTS 
vni  MEN  OF  AcHiEVEMENT-Tte\vELERS  #  EXPLORERS 
ix  HEROES  AND  HEROISM 
X;  PATRIOTISM  #  CITIZENSHIP 


ACfilhVhML 
INVENTORS 
AND  SCIENTISTS 

TTH  AN  INTRODVCTIO 
Al  FRF!)  RlISSFI  W4F  f  4( 


LIBRARY 
OF  INSPIRATION 

•  A.ND   • 

ACHIEVEMENT 


MEN  OF 
ACHIEVEMENT.- 
INVENTORS 
AND  SCIENTISTS 


WITH  AN  INTRODVCTION  • 

•   BY    • 

ALFRED  RUSSELWAIIACE 


THE 

VNIVERSITY  SOCIETY 


78   FIFTH  AVENVE 
NEW  YORK 


Copyright,  1902,  by  The  University  Society 


Copyright,  1898,  by  Docld,  Mead  &  Co. 


Copyright,  1899,  by  Doubleday  &  McClure  Co. 


Cbpyricht,  1899,  by  Fords,  Howard  £  Hulbert 


Copyright,  1900,  by  Fords,  Howard  Si  Hulbert 


v-7 


ASSOCIATE  EDITORS: 

DUFFIELD  OSBORNE,  Novelist  and  Editor. 
CHARLES  G.  D.  ROBERTS,  Writer  of  Animal  Stories. 
HAMILTON  WRIGHT  MABIE,  Associate  Editor  "The  Outlook.1 
EDWARD  W.  BOK,  Editor  "  Ladies  Home  Journal." 
EDWARD  EVERETT  HALE,  Jr.,  Professor  at  Union  College. 
OLIVER  H.  G.  LEIGH,  Editor  and  Litterateur. 


ADVISORY  BOARD: 

ROSSITER  JOHNSON,  Editor  "  Little  Classics." 
JOHN  LANCASTER  SPALDING,  Bishop  of  Peoria. 
OLIVE  THORNE  MILLER,  Writer  of  Animal  and  Bird  Life. 
FRANCIS  E.  CLARKE,  President  Society  of  Christian  Endeavor. 
Mrs.  VIRGINIA  TERHUNE  ("Marion  Harland  "),  Author  "Com- 
mon Sense  in  the  Household,"  etc. 
FRANK  R.  STOCKTON,  Novelist. 
TUDOR  JENKS,  Editor  and  Writer  of  Boys'  Stories. 
L.  A.  SHERMAN,  Professor  at  the  University  of  Nebraska. 
RICHARD  BURTON,  Professor  at  the  University  of  Minnesota. 
KATHARINE  LEE  BATES,  Professor  at  Wellesley  College. 
WILLIAM  CRANSTON  LAWTON,  Professor  at  Adelphi  College. 
GEORGE  ^CARY  EGGLESTON,  Novelist. 


M358873 


PARTIAL  LIST  OF  SPECIAL  CONTRIBUTORS: 

Hon.  THEODORE  ROOSEVELT,  President  of  the  United  States. 

Hon.  GROVER  CLEVELAND,  Ex-President  of  the  United  States. 

Hon.  GEORGE  F.  HOAR,  Senator  from  Massachusetts. 

DAVID  STARR  JORDAN,  Ex-President  Leland  Stanford,  Jr., 
University. 

Hon.  JUSTIN  MCCARTHY,  Ex-Member  of  Parliament. 

Gen.  JOSEPH  WHEELER,  United  States  Army. 

Admiral  ROBLEY  D.  EVANS,  United  States  Navy. 

WILLIAM  R.  HARPER,  President  Chicago  University. 

JAMES  J.  HILL,  President  Great  Northern  Railroad. 

H.  H.  VREELAND,  President  Metropolitan  Street  Railway. 

Hon.  SETH  Low,  Mayor  of  New  York. 

The  EARL  OF  DUNRAVEN,  Author  of  "The  Great  Divide," 
"The  Upper  Yellowstone,"  etc. 

CAMILLE  PREVOST,  French  Athletic  Expert. 

RAY  STANNARD  BAKER,  Author  and  Journalist. 

MARGARET  E.  SANGSTER,  Author  of  "The  Art  of  Home- 
Making." 

HERBERT  WELSH,  Editor  of  "  City  and  State." 

WILLIAM  BLAIKIE,  Author  of  "  How  to  Get  Strong  and  How 
to  Stay  So." 

NICHOLAS  MURRAY  BUTLER,  President  Columbia  University. 

JAMES  B.  ANGELL,  President  University  of  Michigan. 

ANDREW  LANG,  Author. 

JACOB  A.  Rus,  Author  and  Journalist. 

ROBERT  C.  OGDEN,  Partner  of  John  Wanamaker. 

GEORGE  G.  WILLIAMS,  President  Chemical  National  Bank. 

H.  N.  HIGINBOTHAM,  Marshall  Field  &  Co. 

Sir  THOMAS  LIPTON,  London,  England. 

Dr.  GEORGE  F.  SHRADY,  Physician,  New  York. 

Rev.  NEWELL  DWIGHT  HILLIS,  Pastor  Plymouth  Church. 

WALTER  CAMP,  Author  "  College  Sports,"  etc. 

SARAH  K.  BOLTON,  Biographical  Writer. 

And  more  than  two  hundred  other  well-known  writers  and 
successful  business  men. 


INTRODUCTION 


By  ALFRED  RUSSEL  WALLACE 

A  COMPREHENSIVE  review  of  the  practical  discoveries 
and  striking  generalizations  of  science  which  have  in  so 
many  respects  changed  the  outward  forms  of  our  civilization, 
places  us  in  a  position  to  sum  up  the  achievements  of  the 
nineteenth  century  and  compare  them  with  what  has  gone 
before. 

Taking  first  those  inventions  and  practical  applications  of 
science  which  are  perfectly  new  departures,  and  which  have 
also  so  rapidly  developed  as  to  have  profoundly  affected  many 
of  our  habits,  and  even  our  thoughts  and  our  language,  we  find 
them  to  be  thirteen  in  number. 

1 .  Railways,  which  have  revolutionized  land  travel  and  the 
distribution  of  commodities. 

2.  Steam  navigation,  which  has  done  the  same  thing  for 
ocean  travel,  and  has  besides  led  to  the  entire  reconstruction  of 
the  navies  of  the  world. 

3.  Electric  telegraphs,  which  have  produced  an  even  greater 
revolution  in  the  communication  of  thought. 

4.  The  telephone,  which  transmits,  or  rather  reproduces, 
the  voice  of  the  speaker  at  a  distance. 

5.  Friction  matches,  which  have  revolutionized  the  modes 
of  obtaining  fire. 

6.  Gas  lighting,  which  enormously  improved  outdoor  and 
other  illumination. 

7.  Electric  lighting,  another  advance,  now  threatening  to 
supersede  gas. 

8.  Photography,  an  art  which  is  to  the  external  forms  of 
nature  what  printing  is  to  thought. 

vii 


viii  ACHIEVEMENTS  IN  SCIENCE 

9.  The  phonograph,  which  preserves  and  reproduces  sounds 
as  photography  preserves  and  reproduces  forms. 

10.  The  Rontgen  rays,  which  render  many  opaque  objects 
transparent,  and  open  up  a  new  world  to  photography. 

11.  Spectrum  analysis,  which  so  greatly  extends  our  knowl- 
edge of  the  universe  that  by  its  assistance  we  are  able  to 
ascertain  the   relative  heat  and  chemical  constitution  of  the 
stars,  and  ascertain  the  existence,  and  measure  the  rate  of  mo- 
tion, of  stellar  bodies  which  are  entirely  invisible. 

12.  The  use  of  anaesthetics,  rendering  the  most  severe  sur- 
gical operations  painless. 

13.  The  use  of  antiseptics  in  surgical  operations,  which  has 
still  further  extended  the  means  of  saving  life. 

Now,  if  we  ask  what  inventions  comparable  with  these  were 
made  during  the  previous  (eighteenth)  century,  it  seems  at 
first  doubtful  whether  there  were  any.  But  we  may  perhaps 
admit  the  development  of  the  steam  engine  from  the  rude  but 
still  useful  machine  of  Newcomen  to  the  powerful  and  economi- 
cal engines  of  Boulton  and  Watt.  The  principle,  however,  was 
known  long  before,  and  had  been  practically  applied  in  the  pre- 
vious century  by  the  Marquis  of  Worcester  and  by  Savery; 
and  the  improvements  made  by  Watt,  though  very  important, 
had  a  very  limited  result.  The  engines  made  were  almost 
wholly  used  in  pumping  the  water  out  of  deep  mines,  and  the 
bulk  of  the  population  knew  no  more  of  them,  nor  derived 
any  more  direct  benefit  from  them,  than  if  they  had  not 
existed. 

In  the  seventeenth  century,  the  one  great  and  far-reaching 
invention  was  that  of  the  telescope,  which,  in  its  immediate 
results  of  extending  our  knowledge  of  the  universe  and  giving 
possibilities  of  future  knowledge  not  yet  exhausted,  may  rank 
with  spectrum  analysis  in  our  own  era.  The  barometer  and 
thermometer  are  minor  discoveries. 

In  the  sixteenth  century  we  have  no  invention  of  the  first 
rank,  but  in  the  fifteenth  we  have  printing. 

The  mariner's  compass  was  invented  early  in  the  fourteenth 
century,  and  was  of  great  importance  in  rendering  ocean  navi- 
gation possible  and  thus  facilitating  the  discovery  of  America. 


INTRODUCTION  ix 

Then,  backward  to  the  dawn  of  history,  or  rather  to  prehis- 
toric times,  we  have  the  two  great  engines  of  knowledge  and 
discovery — the  Indian  or  Arabic  numerals  leading  to  arithmetic 
and  algebra,  and,  more  remote  still,  the  invention  of  alphabeti- 
cal writing. 

Summing  these  up,  we  find  only  five  inventions  of  the  first 
rank  in  all  preceding  time — the  telescope,  the  printing  press, 
the  mariner's  compass,  Arabic  numerals,  and  alphabetical  writ- 
ing, to  which  we  may  add  the  steam  engine  and  the  barometer, 
making  seven  in  all,  as  against  thirteen  in  our  single  century. 

Coming  now  to  the  theoretical  discoveries  of  our  time, 
which  have  extended  our  knowledge  or  widened  our  concep- 
tions of  the  universe,  we  find  them  to  be  about  equal  in  num. 
ber,  as  follows : 

1.  The  determination  of  the  mechanical  equivalent  of  heat, 
leading  to  the  great  principle  of  the  conservation  of  energy. 

2.  The  molecular  theory  of  gases. 

3.  The  mode  of  direct  measurement  of  the  velocity  of 
Light,  and  the  experimental  proof  of  the  earth's   rotation. 
These  are  put  together,  because  hardly  sufficient  alone. 

4.  The  discovery  of  the  function  of  dust  in  nature. 

5.  The    theory  of  definite  and    multiple    proportions  in 
chemistry. 

6.  The  nature  of  meteors  and  comets,  leading  to  the  meteo- 
ritic  theory  of  the  universe. 

7.  The  proof  of  the  glacial  epoch,  its  vast  extent,  and  its 
effects  upon  the  earth's  surface. 

.8.  The  proof  of  the  great  antiquity  of  man. 

9.  The  establishment  of  the  theory  of  organic  evolution. 

10.  The  cell  theory  and  the  recapitulation  theory  in  em- 
bryology. 

11.  The  germ  theory  of  the  zymotic  diseases. 

12.  The  discovery  of  the  nature  and  function  of  the  white 
blood  corpuscles. 

Turning  to  the  past,  in  the  eighteenth  century  we  may  per- 
haps claim  two  groups  of  discoveries : 

i.  The  foundation  of  modern  chemistry  by  Black,  Caven- 
dish, Priestley,  and  Lavoisier;  and 


x  ACHIEVEMENTS  IN  SCIENCE 

2.  The  foundation  of  electrical  science  by  Franklin,  Gal- 
vani,  and  Volta. 

The  seventeenth  century  is  richer  in  epoch-making  dis- 
coveries, since  we  have 

3.  The  theory  of  gravitation  established. 

4.  The  discovery  of  Kepler's  laws. 

5.  The  invention  of  fluxions  and  the  differential  calculus. 

6.  Harvey's  proof  of  the  circulation  of  the  blood. 

7.  Roemer's  proof  of  finite  velocity  of  light  by  Jupiter's 
satellites. 

Then,  going  backward,  we  can  find  nothing  of  the  first  rank 
except  Euclid's  wonderful  system  of  geometry,  derived  from 
earlier  Greek  and  Egyptian  sources,  and  perhaps  the  most  re- 
markable mental  product  of  the  earliest  civilizations ;  to  which 
we  may  add  the  introduction  of  Arabic  numerals,  and  the  use 
of  the  alphabet.  Thus  in  all  past  history  we  find  only  eight 
theories  or  principles  antecedent  to  the  nineteenth  century  as 
compared  with  twelve  during  that  century.  It  will  be  well 
now  to  give  comparative  lists  of  the  great  inventions  and  dis- 
coveries of  the  two  eras,  adding  a  few  others  to  those  above 
enumerated. 

OF  THE  NINETEENTH  OF  ALL  PRECEDING 

CENTURY.  AGES. 

1.  Railways.  i.  The  mariner's  compass. 

2.  Steamships.  2.  The  steam  engine. 

3.  Electric  telegraphs.  3.  The  telescope. 

4.  The  telephone.  4.  The  barometer  and  ther- 

5.  Lucifer  matches.  mometer. 

6.  Gas  illumination.  5.  Printing. 

7.  Electric  lighting.  6.  Arabic  numerals. 

8.  Photography.  7.  Alphabetical  writing. 

9.  The  phonograph.  8.  Modern  chemistry 

10.  The  Rontgen  rays.  founded. 

11.  Spectrum  analysis.  9.  Electric  science  founded. 

12.  Anaesthetics.  10.  Gravitation  established. 

13.  Antiseptic  surgery.  n.  Kepler's  laws. 


INTRODUCTION 


The  differential  calculus. 

The  circulation  of  the 
blood. 

Light  proved  to  have 
finite  velocity. 

The  development  of  ge- 
ometry. 


14.  Conservation  of  energy.         12. 

15.  Molecular  theory  of  gases.     13. 

1 6.  Velocity  of  light  directly 

measured,   and    earth's     14. 
rotation  experimentally 
shown.  15. 

17.  The  uses  of  dust. 

1 8.  Chemistry,    definite    pro- 

portions. 

19.  Meteors  and  the   meteo- 

ritic  theory. 

20.  The  glacial  epoch. 

21.  The  antiquity  of  man. 

22.  Organic   evolution   estab- 

lished. 

23.  Cell   theory  and    embry- 

ology. 

24.  Germ  theory  of  disease, 

and  the  function  of  the 
leucocytes. 


Of  course  these  numbers  are  not  absolute.  Either  series 
may  be  increased  or  diminished  by  taking  account  of  other  dis- 
coveries as  of  equal  importance,  or  by  striking  out  some  which 
may  be  considered  as  below  the  grade  of  an  important  or  epoch- 
making  step  in  science  or  civilization.  But  the  difference  be- 
tween the  two  lists  is  so  large  that  probably  no  competent 
judge  would  bring  them  to  an  equality.  Again,  it  is  noteworthy 
that  nothing  like  a  regular  gradation  is  perceptible  during  the 
last  three  or  four  centuries.  The  eighteenth  century,  instead 
of  showing  some  approximation  to  the  wealth  of  discovery  in 
our  own  age,  is  less  remarkable  than  the  seventeenth,  having 
only  about  half  the  number  of  really  great  advances. 

It  appears  then  that  the  statement  made  by  me  elsewhere, 
that  for  adequate  comparison  with  the  nineteenth  century  we 
must  take,  not  any  preceding  century  or  group  of  centuries, 
but  rather  the  whole  preceding  epoch  of  human  history,  is  jus- 
tified, and  more  than  justified,  by  the  comparative  lists  now 


xii  ACHIEVEMENTS  IN  SCIENCE 

given.  And  if  we  take  into  consideration  the  change  effected 
in  science,  in  the  arts,  in  all  the  possibilities  of  human  inter- 
course, and  in  the  extension  of  our  knowledge,  both  of  our 
earth  and  of  the  whole  visible  universe,  the  difference  shown 
by  the  mere  numbers  of  these  advances  will  have  to  be  con- 
siderably increased  on  account  of  the  marvelous  character  and 
vast  possibilities  of  further  development  of  many  of  our  recent 
discoveries. 


NOTE    BY   EDITOR 

From  a  summary  of  nineteenth-century  progress  by  Pro- 
fessor Ludwig  Buchner,  of  Germany,  we  take  the  following 
passages,  which  supplement  Professor  Wallace's  statements : 

"The  improved  telescopes  of  the  present  time  have  pro- 
vided us  with  such  an  intimate  knowledge  of  the  constitution 
of  the  surface  of  our  moon  that  it  is  now  better  known  than 
some  parts  of  the  surface  of  the  earth — as  in  the  interior  of  the 
great  continents  of  Africa,  Australia,  and  America.  Similar 
information,  though  to  be  taken  with  reserve,  was  obtained 
from  the  remarkable  phenomena  observed  on  the  surface  of  the 
planet  Mars.  The  interpretation  of  these  features  has  not  been 
thus  far  absolutely  settled,  but  in  the  opinion  of  eminent  as- 
tronomers they  indicate  the  presence  on  that  planet  of  thinking 
beings.  [Further  reference  to  this  subject  will  be  found  in  the 
section  on  Astronomy.]  To  the  nineteenth  century  also  be- 
longs the  somewhat  older  discovery  of  the  planet  Neptune, 
which  was  made  in  such  a  wonderful  way  by  Leverrier  and 
Galle  in  1846.  This  discovery  must  be  regarded  as  one  of  the 
greatest  triumphs  of  astronomical  science,  since  it  was  the 
fruit  of  a  demonstration  by  mathematical  calculations  of  the 
existence  of  a  heavenly  body,  while  the  actual  finding  and 
identification  of  it  were  achieved  afterward  by  means  of  the 
telescope. 


INTRODUCTION  xiii 

The  nineteenth  century  witnessed  the  union  of  electric  force 
with  chemistry  and  technics  in  the  form  of  electro-chemistry 
and  electro-technics,  which  open  the  brightest  vistas  into  the 
future.  For  the  wonderful  force  of  electricity  excels  in  readi- 
ness of  application  and  utility  all  other  forces  of  nature,  and 
beyond  any  other  vanquishes  the  checking  barriers  of  space 
and  time.  It  can,  without  any  special  means,  be  almost  directly 
derived  from  or  changed  into  all  other  forms  of  natural  force, 
and  proceeds  with  an  extraordinary  velocity  through  the  pre- 
scribed paths  of  the  conducting  wires.  It  can,  therefore,  at 
any  moment  be  conducted  to  any  place  where  its  effect  is  re- 
quired. Dwellings  are  now  illuminated  by  electricity  almost 
everywhere,  and  if  heating  by  the  same  agent  and  the  cooking 
of  food  by  means  of  it  become  common,  then  is  foreshadowed 
an  almost  paradisiacal  state,  in  place  of  the  conditions  of  exist- 
ence now  prevailing  with  their  attendant  trouble,  uncleanliness, 
dust,  vexation,  and  disease.  And  should  electro-technics  suc- 
ceed— as  there  is  well-founded  hope  that  it  will — in  solving  the 
problem  of  obtaining  electricity  direct  from  the  fuel,  instead  of 
by  an  expensive  indirect  method  as  heretofore,  the  far-reaching 
effect  of  such  success  can  scarcely  be  overestimated.  As  with 
respect  to  material  progress  the  past  century  is  fittingly  called 
the  century  of  steam,  so  most  likely  the  twentieth  will  have 
to  be  designated  the  century  of  electricity,  when  the  more  ex- 
tended control  of  the  forces  of  nature  by  the  human  mind  shall 
have  taken  an  immense  stride  in  the  forward  direction.  If  we 
add  to  all  this  that  the  grand  material  as  well  as  intellectual 
development  of  the  great  land  of  liberty  in  the  far  West  of  our 
globe,  the  like  of  which  has  never  been  seen  before,  promises 
to  continue  in  the  same  or  even  a  higher  degree,  then  the  men 
of  the  new  century  will  of  necessity  be  more  profoundly  im- 
pressed than  the  children  of  the  present  by  the  achievements 
of  human  intellect  and  human  power. 


CONTENTS 


MODES  OF  TRAVELING 

PAGE 

Primitive  and  Modern  Locomotion i 

By  Alfred  Russel  Wallace. 

The  Motor  Vehicle 9 

By  Ray  Stannard  Baker. 

The  Flying  Machine 23 

By  Ray  Stannard  Baker. 

What  Keeps  the  Bicycler  Upright 33 

By  Charles  B.  Warring. 


CONVEYANCE  OF  THOUGHT 

From  Mail  Coach  to  Telephone 45 

By  Alfred  Russel  Wallace. 

Wireless  Telegraphy 5 l 

By  Ray  Stannard  Baker. 

Sound 64 

By  Elisha  Gray. 

How  the  Telephone  Talks ^\ 

By  Elisha  Gray. 

XV 


xvi  CONTENTS 

-LABOR-SAVING   MACHINERY 

PAGE 

The  Wonder-Working  Wheel  .  .        .      76 

By  Alfred  Russel  Wallace. 

Printing,  Past  and  Present 80 

By  John  Timbs. 

Shoemaking  Machines      .        .  .        • .      •        -9° 

By  Earl  Mayo. 

LIGHT  AND   ITS  USES 

New  Light  on  Light,  or  Revelations  of  Spectrum  Analysis,     i oo 
By  Alfred  Russel  Wallace. 

Color 

By  Elisha  Gray. 

The^r-Rays .  •     II6 

By  John  Trowbridge. 

.r-Ray  Photography I22 

By  Ray  Stannard  Baker. 

The  Eye  as  an  Optical  Instrument  ...  .129 

By  Austin  Flint. 

ASTRONOMY 

Discoveries  in  the  Heavens 138 

By  Alfred  Russel  Wallace. 

The  Planet  Mars       .        .        .        .        .        .        .        .144 

By  Sir  Robert  Ball. 

The  Starry  Heavens 149 

By  Sir  Robert  Ball. 

Comets .166 

By  Camille  Flammarion. 


CONTENTS  xvii 

GEOLOGY 

PAGE 

The  Glacial  Epoch  and  Primitive  Man      .        .        .         .173 
By  Alfred  Russel  Wallace. 

Coal   .  .        .     192 

By  Elisha  Gray., 

On  a  Piece  of  Chalk          . 198 

By  T.  H.  Huxley. 

Volcanoes 221 

By  L.  Agassiz. 

Composition  and  Material  of  the  Earth's  Crust        .         .    230 
By  Agnes  Giberne. 

PHYSICAL  GEOGRAPHY 

The  Atmosphere 257 

By  Elisha  Gray. 

Wind— Why  it  Blows 262 

By  Elisha  Gray. 

Mirage 268 

By  Elisha  Gray. 

Rain  and  Snow 273 

By  John  Tyndall. 

Tides 283 

By  Elisha  Gray. 

Why  Ice  Floats 287 

By  Elisha  Gray. 

Franklin's  Kite  Modernized 290 

By  Alexander  McAdie. 

CHEMISTRY 

Marvels  of  Modern  Chemistry 296 

By  Alfred  Russel  Wallace. 


xviii  CONTENTS 

PAGE 

Ancient  and  Medieval  Chemistry 301 

By  M.  P.  E.  Berthelot. 

Chemical  History  of  a  Candle  (Selection)        .        .        .315 
By  Michael  Faraday. 

Liquid  Air 318 

By  Ira  Remsen. 

The  Potter's  Art 333 

By  Martha  Washington  Levy. 

EVOLUTION  AND  NATURE  STUDIES 

Origin  of  the  Darwinian  Theory 339 

By  Alfred  Russel  Wallace. 

Bees  in  the  Hive 345 

By  Arabella  B.  Buckley. 

The  Massacre  of  the  Males  (Life  of  the  Bee)          .        .    $57 

By  M.  Maeterlinck. 

White  Ants .        .360 

By  Henry  Drummond. 

The  Habits  of  Ants 369 

By  Sir  John  Lubbock. 

Spiders  and  Their  Ways 373 

By  Margaret  Went  worth  Leighton. 

The  Nocturnal  Migration  of  Birds    .        .        .        .        .     381 
By  Frank  M.  Chapman. 

Wingless  Birds 388 

By  Phillippe  Glangeaud. 

The  Cobra  and  Other  Serpents         .        .        .        .        .    393 

By  G.  R.  O'Reilly. 

The  Serpentlike  Sea-Saurians 407 

By  William  H.  Ballou. 

Biographies        .  .  .419 


CELEBRATED   AND   UNIQUE  MANUSCRIPT   AND, 
BOOK  ILLUSTRATIONS. 

A  series  of  fac-similes,  showing  the  development  of  manuscript  and  book 
illustrating  during  a  thousand  years. 


ANTIQUE    VASE  PAINTING. 

A  Rehearsal  in  an  Early  Greek  Theatre. 

As  the  modern  drama  is  a  development  from  the  religious  mystery  plays 
of  the  Middle  Ages,  so  the  Greek  drama  was  an  outgrowth  from  the  religious 
exercises  of  the  worship  of  the  god  Dionysos.  Both  comedy  and  tragedy 
were  considered  of  divine  origin,  and  both  originated  in  the  dithyramb  of 
Dionysos — by  turns  a  merry  song,  celebrating  the  gift  of  the  vine  and  the 
license  of  intoxication,  and  a  funeral  chant  in  memory  of  the  sufferings  of 
the  god  slain  by  the  Titans,  his  descent  into  the  kingdom  of  Hades  and  his 
subsequent  return  to  earth. 

The  upper  picture  is  from  a  vase  of  the  form  known  as  Aryballus,  and 
represents  the  deity  surrounded  by  his  followers.  The  vase  was  exhumed 
in  Athens,  and  is  now  in  the  Berlin  Museum.  The  lower  portion  is  from  a 
vase  in  the  Museum  at  Naples.  In  the  centre  is  the  actor  who  represents 
the  god,  and  presides  over  the  festival;  he  lies  upon  a  couch  with  Ariadne 
beside  him.  The  figure  on  his  left  holding  a  mask  is  the  Muse  of  Tragedy, 
to  whom  a  small  winged  attendant  is  presenting  a  wreath.  Beyond  the 
muse  are  Hercules  and  Silenus.  On  the  other  side  are  an  unidentified  hero 
and  several  actors.  In  front  are  the  members  of  the  chorus,  dressed  as 
satyrs.  One  of  them  is  practising  the  characteristic  dance,  under  the  super- 
vision of  the  chorus-master,  who  is  seated  and  holds  a  baton. 


I 


ILLUSTRATIONS 


WATT  DISCOVERING  THE  POWER  OF  STEAM          Frontispiece 
Photo-engraving  in  colors  from  a  painting  by 
Marcus  Stone 

FACING   PAGB 

ANTIQUE  VASE  PAINTING xviii 

LANGLEY'S  AERODROME 30 

Carbon-print  from  a  photograph 

RECEIVING  A  WIRELESS  MESSAGE          .        .        .        .56 
Carbon-print  from  a  photograph 

GUTENBERG— THE  FIRST  PRINTER          ....      82 
Carbon-print  from  a  steel-engraving 

SIR  RICHARD  PROCTOR  142 

Carbon-print  from  a  photograph 

ALFRED  RUSSEL  WALLACE 174 

Carbon-print  from  a  photograph 

THOMAS  H.  HUXLEY 200 

Carbon-print  from  a  photograph 

EDISON  IN  His  LABORATORY          .....    270 

Carbon-print  from  a  photograph 

A  GRECIAN  POTTER 336 

Photo-engraving  in  colors  from  a  painting  by 
Paul  Thumann 

xix 


MODES  OF  TRAVELING 


Primitive  and  Modern  Locomotion 

By  ALFRED  RUSSEL  WALLACE 

WE  men  of  the  nineteenth  century  have  not  been  slow  to 
praise  it.  The  wise  and  the  foolish,  the  learned  and 
the  unlearned,  the  poet  and  the  pressman,  the  rich  and  the 
poor,  alike  swell  the  chorus  of  admiration  for  the  marvelous 
inventions  and  discoveries  of  our  own  age,  and  especially  for 
those  innumerable  applications  of  science  which  now  form 
part  of  our  daily  life,  and  which  remind  us  every  hour  of  our 
immense  superiority  over  our  comparatively  ignorant  fore- 
fathers. 

But  though  in  this  respect  (and  in  many  others)  we  un- 
doubtedly think  very  well  of  ourselves,  yet,  in  the  opinion  of 
the  present  writer,  our  self-admiration  does  not  rest  upon  an 
adequate  appreciation  of  the  facts.  In  order  to  estimate  its  full 
importance  and  grandeur — more  especially  as  regards  man's 
increased  power  over  nature,  and  the  application  of  that  power 
to  the  needs  of  his  life  to-day,  with  unlimited  possibilities  in 
the  future — we  must  compare  it,  not  with  any  preceding  cen- 
tury, or  even  with  the  last  millennium,  but  with  the  whole  his- 
torical period — perhaps  even  with  the  whole  period  that  has 
elapsed  since  the  stone  age. 

Looking  back  through  the  long  dark  vista  of  human  history, 
the  one  step  in  material  progress  that  seems  to  be  really  com- 
parable in  importance  with  several  of  the  steps  we  have  just 
made,  was,  when  Fire  was  first  utilized,  and  became  the  servant 
and  the  friend  instead  of  being  the  master  and  the  enemy  of 
man.  From  that  far  distant  epoch  even  down  to  our  day,  fire, 
1  1 


2  ACHIEVEMENTS  IN  SCIENCE 

in  various  forms  and  in  ever-widening  spheres  of  action,  has 
not  only  ministered  to  the  necessities  and  the  enjoyments  of 
man,  but  has  been  the  greatest,  the  essential  factor,  in  that 
continuous  increase  of  his  power  over  nature,  which  has  un- 
doubtedly been  a  chief  means  of  the  development  of  his  intel- 
lect and  a  necessary  condition  of  what  we  term  civilization. 
Without  fire  there  would  have  been  neither  a  bronze  nor  an 
iron  age,  and  without  these  there  could  have  been  no  effective 
tools  or  weapons,  with  all  the  long  succession  of  mechanical 
discoveries  and  refinements  that  depended  upon  them.  With- 
out fire  there  could  be  no  rudiment  even  of  chemistry,  and  all 
that  has  arisen  out  of  it.  Without  fire  much  of  the  earth's  sur- 
face would  be  uninhabitable  by  man,  and  much  of  what  is  now 
wholesome  food  would  be  useless  to  him.  Without  fire  he 
must  always  have  remained  ignorant  of  the  larger  part  of  the 
world  of  matter  and  of  its  mysterious  forces.  He  might  have 
lived  in  the  warmer  part  of  the  earth  in  a  savage  or  even  in  a 
partially  civilized  condition,  but  he  could  never  have  risen  to 
the  full  dignity  of  intellectual  man,  the  interpreter  and  master 
of  the  forces  of  nature. 

Having  thus  briefly  indicated  our  standpoint,  let  us  proceed 
to  sketch  in  outline  those  great  advances  in  science  and  the  arts 
which  are  the  glory  of  our  century.  In  the  course  of  our  sur- 
vey we  shall  find  that  the  more  important  of  these  are  not  mere 
improvements  upon,  or  developments  of,  anything  that  had 
been  done  before,  but  that  they  are  entirely  new  departures, 
arising  out  of  our  increasing  knowledge  of  and  command  over 
the  forces  of  the  universe.  Many  of  these  advances  have 
already  led  to  developments  of  the  most  startling  kind,  giving 
us  such  marvelous  powers,  and  such  extensions  of  our  normal 
senses,  as  would  have  been  incredible,  and  almost  unthinkable 
even  to  our  greatest  men  of  science,  a  hundred  years  ago.  We 
begin  with  the  simplest  of  these  advances,  those  which  have 
given  us  increased  facilities  for  locomotion. 

The  younger  generation,  which  has  grown  up  in  the  era  of 
railways  and  of  ocean-going  steamships,  hardly  realize  the  vast 
change  which  we  elders  have  seen,  or  how  great  and  funda- 
mental that  change  is.  Even  in  my  own  boyhood  the  wagon 


MODES  OF  TRAVELING  3 

for  the  poor,  the  stage  coach  for  the  middle  class,  and  the  post- 
chaise  for  the  wealthy,  were  the  universal  means  of  communi- 
cation, there  being  only  two  short  railways  then  in  existence — 
the  Stockton  and  Darlington  opened  in  1825,  and  the  Liver- 
pool and  Manchester  line  opened  in  1830.  The  yellow  post- 
chaise,  without  any  driving  seat,  but  with  a  postilion  dressed 
like  a  jockey  riding  one  of  the  pair  of  horses,  was  among  the 
commonest  sights  on  our  main  roads ;  and  together  with  the 
hundreds  of  four-horse  mail  and  stage  coaches,  the  guards 
carrying  horns  or  bugles  which  were  played  while  passing 
through  every  town  or  village,  gave  a  stir  and  liveliness  and 
picturesqueness  to  rural  life  which  is  now  almost  forgotten. 

When  I  first  went  to  London  (about  1835)  there  was  still 
not  a  mile  of  railroad  in  England,  except  the  two  above  named, 
and  none  between  London  and  any  of  our  great  northern  or 
western  cities  were  even  seriously  contemplated.  The  sites  of 
most  of  our  great  London  railway  termini  were  then  on  the 
very  outskirts  of  the  suburbs. 

A  few  years  later,  while  the  London  and  Birmingham  Rail- 
way, the  precursor  of  the  present  London  and  Northwestern 
system,  was  in  process  of  construction ;  and  when  the  first  sec- 
tion was  opened  to  Watford,  I  traveled  by  it  to  London,  third- 
class,  in  what  is  now  an  ordinary  goods  truck,  with  neither  roof 
nor  seats,  nor  any  other  accommodation  than  is  now  given  to 
coal,  iron,  and  miscellaneous  goods.  If  it  rained,  or  the  wind 
was  cold,  the  passengers  sat  on  the  floor  and  protected  them- 
selves as  they  could.  Second-class  carriages  were  then  what 
the  very  worst  of  the  third  class  are  or  were  a  few  years  ago — 
closed  in,  but  low  and  nearly  dark,  with  plain  wooden  seats — 
while  the  first-class  were  exactly  like  the  bodies  of  three  stage 
coaches  joined  together.  The  open  passenger  trucks  were  the 
cause  of  much  misery,  and  a  few  deaths  from  exposure,  before 
they  were  somewhat  improved ;  but  even  then  there  was  evi- 
dently a  dread  of  making  them  too  comfortable,  so  a  roof  was 
put  to  them,  also  seats,  and  the  sides  a  little  raised  but  open  at 
the  top,  about  equal  in  comfort  to  our  present  cattle  trucks. 
At  last,  after  a  good  many  years,  the  despised  third-class  pas- 
sengers were  actually  provided  with  carriages  of  the  earlv  sec- 


4  ACHIEVEMENTS  IN  SCIENCE 

ond-class  type;  and  it  is  only  in  comparatively  recent  times 
that  the  greater  railway  companies  realized  the  fact  that  third- 
class  passengers  were  so  numerous  as  to  be  more  profitable 
than  the  other  two  combined,  and  that  it  was  worth  while  to 
give  them  the  same  comfort,  if  not  the  same  luxury,  as  those 
who  could  afford  to  travel  more  expensively. 

The  continuous  progress  in  speed  and  comfort  is  matter  of 
common  knowledge,  and  nothing  more  need  be  said  of  it  here. 
The  essential  point  for  our  consideration  is,  the  fundamental 
and  even  revolutionary  nature  of  the  change  that  has  been 
wholly  effected  during  the  present  century.  In  all  previous 
ages  the  only  modes  of  traveling  or  of  conveying  goods  for 
long  distances  were  by  employing  either  men  or  animals  as  the 
carriers.  Wherever  the  latter  were  not  used,  all  loads  had  to 
be  carried  by  men,  as  is  still  the  case  over  a  large  part  of 
Africa,  and  as  was  the  case  over  almost  the  whole  of  America 
before  its  discovery  by  the  Spaniards. 

But  throughout  Europe  and  Asia  the  horse  was  domesti- 
cated in  very  early  times,  and  was  used  for  riding  and  in  draw- 
ing war-chariots ;  and  throughout  the  Middle  Ages  pack-horses 
were  in  universal  use  for  carrying  various  kinds  of  goods  and 
produce,  and  saddle  horses  for  riding.  All  journeys  were  then 
made  on  horseback,  and  it  was  in  comparatively  recent  times 
that  wheeled  vehicles  for  traveling  came  into  general  use  in 
England.  The  very  first  carriage  was  made  for  Queen  Eliza- 
beth in  1568;  the  first  that  plied  for  hire  in  London  were  in 
1625,  and  the  first  stage  coaches  in  1659. 

But  chariots  drawn  by  horses  were  used,  both  in  war  and 
peace,  by  all  the  early  civilized  peoples.  Pharaoh  made  Joseph 
ride  in  a  chariot,  and  he  sent  wagons  to  bring  Jacob,  with  his 
children  and  household  goods,  to  Egypt.  A  little  later,  char- 
iots were  sent  by  the  Syrians  as  tribute  to  Pharaoh.  Homer 
describes  Telemachus  as  traveling  from  Pylos  to  Sparta  in  a 
chariot  provided  for  him  by  Nestor: 

The  rage  of  thirst  and  hunger  now  suppress'd, 
The  monarch  turns  him  to  his  royal  guest ; 
And  for  the  promis'd  journey  bids  prepare 
The  smooth-haired  horses,  and  the  rapid  car. 


MODES  OF  TRAVELING  5 

It  is  clear,  therefore,  that  in  the  earliest  historic  times  all 
the  various  types  of  wheeled  vehicles  were  used — for  war,  for 
racing,  for  traveling,  and  for  the  conveyance  of  merchandise. 
They  must  also  have  been  used  throughout  a  large  part  of 
Europe,  since  Caesar  found  our  British  ancestors  possessed  of 
war-chariots,  which  they  managed  with  great  skill,  implying  a 
long  previous  acquaintance  with  the  domesticated  horse  and  its 
use  in  humbler  wheeled  vehicles. 

Thus,  throughout  all  past  history  the  modes  of  traveling 
were  essentially  the  same,  and  an  ancient  Greek  or  Roman, 
Egyptian  or  Assyrian,  could  travel  as  quickly  and  as  conveni- 
ently as  could  Englishmen  down  to  the  latter  part  of  the 
eighteenth  century.  It  was  mainly  a  question  of  roads,  and  till 
the  beginning  of  the  nineteenth  century  our  roads  were  for  the 
most  part  far  inferior  to  those  of  the  Romans.  It  is,  therefore, 
not  improbable  that  during  the  Roman  occupation  of  Britain 
the  journey  from  London  to  York  could  have  been  made  actu- 
ally quicker  than  a  hundred  and  fifty  years  ago. 

We  see,  then,  that  from  the  earliest  historic,  and  even  in 
prehistoric  times,  till  the  construction  of  our  great  railways  in 
the  second  quarter  of  the  present  century,  there  had  been  abso- 
lutely no  change  in  the  methods  of  human  locomotion ;  and  the 
speed  for  long  distances  must  have  been  limited  to  ten  or 
twelve  miles  an  hour  even  under  the  most  favorable  conditions, 
while  generally  it  must  have  been  very  much  less.  But  the 
railroad  and  steam-locomotive,  in  less  than  fifty  years,  not  only 
raised  the  speed  to  fifty  or  sixty  miles  an  hour,  but  rendered  it 
possible  to  carry  many  hundreds  of  passengers  at  once  with 
punctuality  and  safety  for  enormous  distances,  and  with  hardly 
any  exposure  or  fatigue.  For  the  civilized  world  traveling  and 
the  conveyance  of  goods  have  been  revolutionized,  and  by 
means  which  were  probably  neither  anticipated  nor  even  im- 
agined fifty  years  before. 

Dr.  Erasmus  Darwin,  who  predicted  steam  carriages,  had 
apparently  no  conception  of  the  possibility  of  railroads,  the 
enormous  cost  of  which  would  have  seemed  to  be  prohibitory. 
And  we  have  by  no  means  yet  fully  developed  their  possibili- 
ties, since  even  now  a  railroad  could  be  made  on  which  we 


6  ACHIEVEMENTS  IN  SCIENCE 

might  safely  travel  more  than  a  hundred  miles  an  hour,  it  being 
merely  a  question  of  expense. 

In  steam  navigation  there  has  been  a  very  similar  course  of 
events,  with  the  same  characteristic  of  a  completely  new  de- 
parture, leading  to  unknown  developments  and  possibilities. 
From  the  earliest  dawn  of  history,  men  used  rowing  or  sailing 
vessels  for  coasting  trade  or  for  crossing  narrow  seas.  The 
Carthaginians  sailed  nearly  to  the  equator  on  the  west  coast  of 
Africa,  and  in  the  eleventh  century  the  Northmen  reached 
North  America  on  the  coast  of  New  England.  Over  five 
hundred  years  ago,  Vasco  de  Gama  sailed  from  Portugal  round 
the  Cape  of  Good  Hope  to  India,  and  in  the  next  century 
Columbus  and  his  Spanish  followers  crossed  the  Atlantic  in  its 
widest  part  to  the  West  Indies  and  Mexico.  From  that  time 
sailing  ships  were  gradually  improved,  till  they  culminated  in 
our  magnificent  frigates  for  war  purposes  and  the  clipper  ships 
in  the  China  and  Australian  trade,  which  were  in  use  up  to  the 
middle  of  the  century.  But  during  all  this  long  course  of  de- 
velopment there  was  no  change  whatever  in  principle,  and  the 
grandest  three-decker  or  full-rigged  clipper  ship  was  but  a 
direct  growth,  by  means  of  an  infinity  of  small  modifications 
and  improvements,  from  the  rudest  sailing  boat  of  the  primeval 
savage. 

Then,  at  the  very  commencement  of  the  present  century, 
the  totally  new  principle  of  steam  propulsion  began  to  be  used, 
first  experimentally  and  with  many  failures,  on  rivers,  canals, 
and  lakes,  till  about  the  year  1815  coasting  steamships  of  small 
size  came  into  pretty  general  use.  These  were  rapidly  im- 
proved; but  it  was  not  till  the  year  1838  that  the  Great  West- 
ern, of  1,340  tons  and  four  hundred  horse-power,  made  the 
passage  from  Bristol  to  New  York  in  fourteen  days,  and  thus 
inaugurated  the  system  of  ocean  steam  navigation  which  has 
since  developed  to  such  an  enormous  extent.  The  average 
speed  then  attained,  of  about  ten  miles  an  hour,  has  now  been 
more  than  doubled,  and  is  still  increasing.  But  the  horse- 
power needed  to  attain  this  high  speed  has  increased  in  much 
greater  proportion ;  and  it  is  only  the  much  greater  size  and 
capacity,  both  for  passengers  and  goods,  that  render  such  high 


MODES  OF  TRAVELING  7 

speeds  and  enormous  consumption  of  coal  profitable.  Some  of 
the  smaller  steel-built  war-ships — torpedo-boats  and  torpedo- 
destroyers — have  considerably  exceeded  thirty  miles  an  hour, 
and  the  limit  of  speed  is  probably  not  yet  reached.  Many  sug- 
gested forms  of  vessels,  such  as  the  cigar-shaped  and  the 
roller  boats,  have  not  been  adequately  tried;  and  there  are 
other  suggested  forms  by  means  of  which  greater  steadiness 
and  speed  may  yet  be  obtained. 

Almost  as  remarkable  as  our  railroads  and  steamships  is  the 
new  method  of  locomotion  by  means  of  the  bicycle  and  tricycle. 
The  principle  is  old  enough,  but  the  perfection  to  which  these 
vehicles  have  now  attained  has  been  rendered  possible  by  the 
continuous  growth  of  all  kinds  of  delicate  tools  and  machines 
required  in  the  construction  of  the  infinitely  varied  forms  of 
steam-engines,  dynamos,  and  other  rapidly  moving  machinery. 
In  the  last  century  it  would  not  have  been  possible  to  construct 
a  modern  first-class  bicycle,  even  if  any  genius  had  invented 
it,  except  at  a  cost  of  several  hundred  pounds.  The  combina- 
tion of  strength,  accuracy,  and  lightness  would  not  then  have 
been  attainable.  It  is  a  very  interesting  fact  that  three  out  of 
the  four  methods  of  rapid  locomotion  we  now  possess  should 
have  attained  about  the  same  maximum  speed.  The  race-horse, 
the  steamship,  and  the  bicycle,  have  each  of  them  reached 
thirty  miles  an  hour.  The  horse  is,  however,  close  upon,  if  it 
has  not  actually  attained,  its  utmost  limits ;  the  bicycle  can 
already  beat  the  horse  for  long  distances,  and  will  certainly  go 
at  higher  speeds  for  short  ones ;  while  the  steamship  will  also 
go  much  quicker,  though  how  much  no  one  can  yet  say.  The 
greatest  possibilities  are  with  the  bicycle,  driven  by  electric 
power  or  compressed  air,  by  which  means,  on  a  nearly  straight 
and  fairly  level  asphalt  track,  no  doubt  fifty  miles  an  hour  will 
soon  be  reached. 

We  see,  then,  that  during  the  nineteenth  century  three  dis- 
tinct modes  of  locomotion  have  been  originated  and  brought  to 
a  high  degree  of  perfection.  Two  of  them,  the  locomotive  and 
the  steamship,  are  altogether  different  in  principle  from  what 
had  gone  before.  Up  to  the  very  times  of  men  now  living,  all 
our  locomotion  was  on  the  same  old  lines  which  had  been  used 


8  ACHIEVEMENTS  IN  SCIENCE 

for  thousands  of  years.  It  had  been  improved  in  details,  but 
without  any  alteration  of  principle  and  without  any  very  great 
increase  of  efficiency.  The  principles  on  which  our  present 
methods  rest  are  new ;  they  already  far  surpass  anything  that 
could  be  effected  by  the  older  methods;  with  wonderful  ra- 
pidity they  have  spread  over  the  whole  world,  and  they  have 
in  many  ways  modified  the  habits  and  even  the  modes  of  speech 
of  all  civilized  peoples. 

This  vast  change  in  the  methods  of  human  locomotion, 
already  so  ubiquitous  that  by  the  younger  generation  their  ab- 
sence rather  than  their  presence  is  considered  remarkable,  has 
been  almost  wholly  effected  within  the  writer's  memory. 


MODES  OF  TRAVELING 


The  Motor  Vehicle 

By  RAY  STANNARD  BAKER 

STEP  up  and  take  your  seat  in  the  world's  very  newest  and 
most  marvelous  vehicle — the  motor  carriage.  As  you  sit 
facing  forward,  where  the  horse  ought  to  be  and  is  not,  your 
right  hand  fits  easily  and  naturally  over  the  smooth  handle  of 
a  lever.  Press  your  thumb  down  hard  on  a  little  button  at  the 
top  and  a  bell  rings  sharply — a  mere  friendly  warning  that  you 
are  about  to  start.  Now  push  the  lever  forward  one  notch  and 
off  you  go,  smoothly  and  steadily,  but  slowly ;  another  notch, 
and  you  are  making  the  speed  of  a  trotting  horse ;  still  another 
notch,  and  you  are  flying  like  the  wind,  far  faster  than  any 
horse  ever  goes  under  harness.  While  your  right  hand  is  thus 
employed  with  the  speeding  lever,  your  left  is  firmly  holding 
the  steering  handle,  swinging  the  vehicle,  this  way  and  that, 
around  corners  and  past  obstacles  as  easily  as  if  it  were  a  bicy- 
cle. If  you  wish  to  stop  suddenly,  your  foot  is  on  a  brake ;  a 
slight  push  and  the  vehicle  comes  to  a  standstill. 

Variations  there  are  in  the  arrangement  of  levers  and  brakes 
in  different  vehicles,  but  they  are  all  equally  simple  of  manage- 
ment. You  can  travel  from  daylight  to  dark  and  never  suffer 
with  a  worn-out  horse ;  you  can  run  away  from  the  dust  and 
escape  the  flies,  and  if  you  reach  a  railroad  crossing  just  as  a 
train  is  passing,  your  motor  carriage  never  takes  fright  and 
runs  away.  When  you  reach  home  there  is  no  troublesome 
unharnessing,  nor  rubbing  down,  and  your  carriage  is  ready  at 
a  second's  notice  to  start  on  a  new  expedition.  And  as  for  the 
carriage  whip,  it  will  follow  the  horse  out  of  existence. 

9 


10  ACHIEVEMENTS  IN  SCIENCE 

Only  a  few  years  ago,  in  1894,  there  were  not  thirty  of 
these  remarkable  vehicles  in  practical  use  in  all  the  world.  At 
the  beginning  of  1898  there  were  not  thirty  in  all  America. 
And  yet  so  great  was  the  success  of  the  inventor,  and  so  wide- 
spread the  interest  of  the  public,  that  the  manufacture  of  motor 
vehicles  suddenly  became  a  great  industry.  In  the  first  four 
months  of  the  year  1899  alone,  corporations  with  the  enormous 
aggregate  capitalization  of  more  than  $300,000,000  were  organ- 
ized in  New  York,  Boston,  Chicago,  and  Philadelphia;  and  in 
many  cities  of  the  East,  motor  vehicles  have  become  so  familiar 
on  the  streets  that  they  are  noticed  hardly  more  than  horse 
carriages.  More  than  that,  motor  ambulances,  motor  trucks, 
motor  gun-carriages,  motor  stages,  and  motor  fire  engines  are 
in  operation  in  various  cities.  In  France  and  England  the 
motor  vehicle  has  become  an  established  and  powerful  factor  in 
the  common  affairs  of  life.  France  has  a  powerful  motor  vehi- 
cle or  "  automobile  "  club  which  gives  frequent  races  and  exhi- 
bitions. At  a  single  gathering  more  than  1,500  vehicles  were 
shown,  representing  every  conceivable  model,  from  milk-wagons 
to  fashionable  broughams  and  the  huge  brakes  of  De  Dion  and 
Bouton,  which  carry  almost  as  many  passengers  as  a  railroad 
car.  Some  of  the  expert  "drivers  "  of  Paris  have  ridden  thou- 
sands of  miles  in  their  road  wagons,  have  climbed  mountains, 
and  raced  through  half  of  Europe,  meeting  new  accidents,  fac- 
ing new  adventures,  and  using  strange  new  devices  for  which 
names  have  yet  to  be  coined. 

The  motor  races  of  Paris  have  been  by  far  the  most  unique 
and  remarkable  that  the  world  has  ever  seen.  Both  M.  Rene 
de  Knyff  and  Count  Chasseloup-Laubat,  of  Paris,  have  made 
sixty  miles  an  hour  on  an  ordinary  road  track.  Just  think  of 
it !  Faster  than  the  Empire  State  Express,  and  that  with  no 
advantage  of  steel  rails  nor  level  road-bed.  But  even  the 
records  of  these  two  famous  racers  have  been  beaten  by  M. 
Jenatzy  with  his  lightning  carriage,  "La  Jamais  Contente" 
("The  Never  Content").  This  wonderful  vehicle  is  built  of 
sheet  iron  in  the  form  of  a  long  cigar  or  torpedo,  so  that  it 
plunges  through  the  air  like  a  dart.  The  wheels  are  very  small 
and,  of  course,  fitted  with  rubber  tires.  There  is  a  manhole  in 


MODES   OF  TRAVELING  11 

the  top  of  the  vehicle,  where  the  driver  sits.  Just  in  front  of 
it  there  is  a  little  steering  wheel  and  electrical  meters  to  show 
the  voltage  and  amperage  of  the  current.  To  see  "  La  Jamais 
Contente  "  one  would  think  that  no  driver  ever  would  dare  to 
risk  his  life  upon  it.  And,  indeed,  after  the  current  is  turned 
on  and  the  wheels  begin  to  revolve,  it  is  either  fly  or  burn,  so 
tremendous  is  the  power  of  the  batteries. 

At  the  famous  record  trial  "La  Jamais  Contente"  was 
towed  out  from  Paris  to  the  racing  road  by  a  humble  petroleum 
car.  M.  Rene  de  Knyff  gave  the  word  to  start.  M.  Jenatzy 
turned  on  the  current  and  braced  himself,  leaning  well  forward, 
with  his  hands  firmly  clasping  the  steering  wheel.  The  car 
moved  off  somewhat  slowly  at  first,  but  after  going  about  ten 
yards,  literally  bounded  forward,  the  wheels  for  a  moment 
almost  leaving  the  track.  There  was  a  blue-gray  streak  down 
the  road,  a  faint  cloud  of  dust,  and  the  famous  carriage  was 
making  more  than  a  mile  a  minute.  The  sound  of  the  motor 
was  described  by  a  spectator  as  resembling  the  rustling  of 
wings,  and  the  car  undulated  like  a  swallow  in  flying,  this  no 
doubt  being  due  to  the  action  of  the  springs  and  the  rubber 
tires.  Nothing  had  ever  before  traveled  on  a  common  road  at 
such  a  speed,  and  the  spectators  were  anxious  to  know,  not 
whether  Jenatzy  had  broken  the  record,  but  by  how  much  he 
had  broken  it.  The  wheels  left  two  broad  white  tracks  in  the 
middle  of  the  road,  absolutely  straight  and  converging  in  the 
distance  like  a  line  of  rails.  It  was  a  remarkable  exhibition  of 
accurate  steering.  Indeed,  if  Jenatzy  had  swerved  an  inch  to 
the  right  or  to  the  left,  he  would  not  have  survived  to  tell  the 
tale.  After  the  trial  was  over,  it  was  found  that  "  La  Jamais 
Contente  "  had  made  sixty-six  miles  an  hour,  and  M.  Jenatzy 
went  away  declaring  that  he  should  soon  make  seventy-five 
miles  an  hour. 

In  general  it  may  be  said  that  France  has  led  in  gasoline 
vehicles,  and  England  in  steam  vehicles,  while  America,  as  was 
to  be  expected,  has  been  far  in  the  lead  in  electrical  convey- 
ances of  all  kinds.  Belgium  and  Germany,  and  to  some  extent 
Austria,  have  also  been  experimenting  with  more  or  less  suc- 
cess, but  no  such  progress  has  been  made  in  these  countries  as 


12  ACHIEVEMENTS  IN  SCIENCE 

in  France.  It  was  not  until  1898  that  Spain  rubbed  its  eyes 
for  the  first  time  at  the  sight  of  a  motor  vehicle,  which  rolled 
through  Madrid  with  half  a  dozen  little  policemen  careering 
after  it. 

In  a  general  way,  it  may  be  said  that  the  best  modern  motor 
vehicle,  whatever  its  propelling  power,  is  practically  noiseless 
and  odorless  and  nearly  free  from  vibrations.  It  is  still  heavy 
and  clumsy  in  appearance,  although  it  is  lighter  than  the  pres- 
ent means  of  conveyance  when  the  weight  of  the  horse  or 
horses  is  counted  in  with  the  carriage.  And  invention  will 
soon  lighten  it  still  further.  It  cannot  possibly  explode.  It 
will  climb  all  ordinary  hills,  and  on  a  level  road  it  will  give  all 
speeds  from  two  miles  an  hour  up  to  twenty  or  more.  Its 
mechanism  has  been  made  so  simple  that  any  one  can  learn  to 
manage  it  in  an  hour  or  two.  And  yet  it  is  mechanism ;  and 
intelligence,  coolness,  and  caution  are  required  to  manage  a 
motor  vehicle  in  a  crowded  street.  The  operator  must  combine 
the  intelligence  of  the  driver  with  that  of  the  horse,  and  he  does 
not  appreciate  the  almost  human  sagacity  of  that  despised  ani- 
mal until  he  has  tried  to  steer  a  motor  vehicle  down  Fifth 
Avenue  on  a  sunny  afternoon. 

Seven  different  motive  powers  are  now  actually  employed 
in  this  country:  electricity,  gasoline,  steam,  compressed  air, 
carbonic-acid  gas,  alcohol,  and  liquid  air.  The  first  three  of 
these  have  been  practically  applied  with  great  success ;  all  the 
others  are  more  or  less  in  the  experimental  stage. 

The  electric  vehicle,  which  has  had  its  most  successful  de- 
velopment in  this  country,  has  its  well-defined  advantages  and 
disadavantages.  It  is  simpler  in  construction  and  more  easily 
managed  than  any  other  vehicle:  one  manufacturer  calls  it 
"  fool-proof."  It  is  wholly  without  odor  or  vibrations  and  prac- 
tically noiseless.  It  will  make  any  permissible  rate  of  speed, 
and  climb  any  ordinary  hill.  On  the  other  hand,  it  is  im- 
mensely heavy,  owing  to  the  use  of  storage  batteries ;  it  can 
run  only  a  limited  distance  without  recharging,  and  it  requires 
a  moderately  smooth  road.  In  cost  it  is  the  most  expensive  of 
all  vehicles.  And  yet  for  city  use,  where  a  constant  supply 
of  electricity  can  be  had,  electrical  cabs,  carriages,  and 


MODES  OF  TRAVELING  13 

delivery   wagons  have  demonstrated  their  remarkable  prac- 
ticability. 

The  vital  feature  of  the  electric  vehicle  is  the  storage  bat- 
tery, which  weighs  from  500  to  1,500  pounds,  the  entire  weight  of 
the  vehicles  varying  from  about  900  to  4,000  pounds.  A  phaeton 
for  ordinary  private  use  will  weigh  upwards  of  a  ton,  with  a 
battery  of  nine  hundred  pounds.  This  immense  weight  re- 
quires exceedingly  rigid  construction  and  high-grade,  expensive 
tires.  The  electrical  current  is  easily  controlled  by  means  of 
a  lever  under  the  hand  of  the  driver,  the  propelling  machinery 
being  comparatively  simple.  When  the  battery  is  nearly 
empty,  it  may  be  recharged  at  any  electric-lighting  station  by 
the  insertion  of  a  plug,  the  time  required  varying  from  two  to 
three  hours.  Or,  if  the  owner  prefers,  he  can  own  his  own 
charging  plant  and  generate  his  own  electricity:  it  will  cost 
him  from  $500  to  $700.  The  current  not  only  operates  the 
vehicle,  but  it  lights  the  lamps,  rings  the  gong,  and  in  cabs  and 
broughams  actuates  a  push-button  arrangement  for  communi- 
cation between  passenger  and  driver.  The  limit  of  travel  with- 
out recharging  is  from  twenty  to  thirty  miles.  A  good  elec- 
tric carriage  for  family  use  cannot  be  obtained  for  much  less 
than  $2,000,  although  one  or  two  manufacturers  advertise  run- 
abouts and  buggies  at  from  $750  to  $1,500.  An  omnibus  costs 
from  $3,000  to  $4,000. 

The  company  which  operates  the  electric  cab  system  in 
New  York  has  a  most  extensive  charging  plant.  Two  batteries 
are  provided  for  each  vehicle,  so  that,  when  one  is  empty,  it 
may  be  removed  by  the  huge  fingers  of  a  traveling  crane, 
placed  on  a  long  table,  and  recharged  at  leisure,  while  a  com- 
pletely filled  battery  is  introduced  in  its  place.  This  change 
takes  only  a  few  minutes,  and  the  cab  can  be  used  continuously 
day  and  night. 

The  "  lightning  cabby  "  is  a  product  of  the  new  industry. 
He  wears  a  blue  uniform  somewhat  resembling  that  of  a  fire- 
man, and  he  is  a  cool-headed,  intelligent  fellow,  who  can  make 
ten  miles  an  hour  in  a  crowded  street  without  once  catching 
the  suspicious  eye  of  a  policeman.  Most  of  the  "  cabbies  "  have 
had  previous  experience  as  drivers,  but  they  are  given  a  very 


14  ACHIEVEMENTS  IN  SCIENCE 

thorough  training  before  they  are  allowed  to  venture  on  the 
streets  with  a  vehicle  of  their  own.  A  special  instructor's  cab 
is  in  use  by  the  company.  It  has  a  flaring  front  platform 
with  a  solid  wooden  bumper,  so  that  it  may  crash  into  a  stone 
curb  or  run  down  a  lamp  post  without  injury.  The  new  man 
perches  himself  on  the  seat  behind,  and  the  instructor  takes 
his  place  inside,  where  he  is  provided  with  a  special  arrange- 
ment for  cutting  off  the  current  or  applying  the  brakes,  should 
the  vehicle  escape  from  the  control  of  the  learner.  It  usually 
takes  a  week  to  train  a  new  man  so  that  he  can  manage  all  the 
brakes  and  levers  with  perfect  presence  of  mind.  Both  of  his 
hands  and  both  of  his  feet  are  fully  employed.  With  his  left 
hand  he  manages  the  power  lever,  pushing  it  forward  one 
notch  at  a  time  to  increase  the  speed.  With  his  right  hand 
he  controls  the  steering  lever,  which,  by  the  way,  turns  the 
rear  wheels  and  not  the  front  ones,  as  is  done  with  horse-pro- 
pelled vehicles.  His  left  heel  is  on  the  emergency  switch,  and 
his  left  toe  rings  the  gong.  With  his  right  heel  he  turns  the 
reversing  switch,  and  he  may  apply  the  brake  with  either  his 
right  or  his  left  foot.  When  he  wishes  to  turn  on  the  lights, 
he  presses  a  button  under  the  edge  of  the  seat.  Hence,  he  is 
very  fully  employed,  both  mentally  and  physically.  He  cannot 
go  to  sleep  and  let  the  old  horse  carry  him  home. 

In  France  the  system  of  instruction  for  drivers  or  chauf- 
feurs (stokers),  as  they  are  called,  is  much  more  complicated 
and  extensive,  but  hardly  more  thorough.  There  the  cab  com- 
pany has  prepared  a  seven-hundred-yard  course  up  hill  and 
down,  and  paved  it  alternately  with  cobbles,  asphalt,  wooden 
blocks,  and  macadam,  so  as  to  give  the  incipient  "  cabby  "  ex- 
perience in  every  difficulty  which  he  will  meet  in  the  streets  of 
Paris.  Upon  the  inclines  are  placed  numerous  lay  figures, 
made  of  iron — a  typical  Parisian  nursemaid  with  a  bassinet ;  a 
bicycle  rider ;  an  old  gentleman  presumably  deaf,  who  is  not 
spry  in  getting  out  of  the  way ;  a  dog  or  two,  and  paper  bricks 
galore.  Down  through  this  throng  must  the  motorman  thread 
his  way  and  clang  his  gong,  and  he  is  not  considered  proficient 
until  he  can  course  the  full  length  of  the  "  Rue  de  Magde- 
bourg,"  as  the  cabbies  call  it,  without  so  much  as  over- 


MODM  OF  TRAVELING  15 

turning  a  singly  pastry  cook's  boy  or  crushing  a  dummy 
brick. 

New  York  cabs  will  run  twenty  miles  without  recharging. 
But  it  is  not  at  all  infrequent  for  a  new  man  to  have  his  vehicle 
stop  suddenly  and  most  unexpectedly ;  the  current  deserts  him 
before  he  knows  it.  He  must  let  the  central  office  know  at 
once,  and  the  ambulance  cab  comes  spinning  out,  hooks  to  the 
helpless  vehicle,  and  drags  it  into  the  charging  station.  One 
manufacturer  has  issued  lists  of  hundreds  of  central  stations 
throughout  New  England,  New  York,  and  other  Eastern  States 
where  automobiles  may  be  provided  with  power. 

In  Belgium  a  company  has  recently  been  formed  to  estab- 
lish electric  posting  stations.  Its  promoters  plan  to  have  a  bar 
and  restaurant  connected  with  the  charging  plant,  a  regular 
medical  attendant,  and  an  expert  mechanic  who  will  know  how 
to  remedy  all  the  ills  of  motor  vehicles.  In  the  larger  cities 
the  time  must  soon  come  when  there  will  be  coin-in-the-slot 
"  hydrants  "  for  electricity  at  many  public  places,  from  which 
owners  of  vehicles  may  charge  their  batteries  while  they  wait. 

A  number  of  prominent  New  York  physicians  own  their 
own  motor  vehicles,  these  being  especially  adapted  to  the  varied 
necessities  of  a  physician's  practice.  A  motor  vehicle  is  always 
ready  at  a  moment's  notice — it  does  not  have  to  be  harnessed. 
It  can  work  twenty-four  hours  a  day.  When  it  is  left  in  the 
street  outside,  the  doctor  takes  with  him  a  little  brass  plug,  or 
key,  without  which  the  vehicle  cannot  run  away  or  be  moved 
or  stolen.  And,  moreover,  it  is  swifter  by  half  than  the  ordi- 
nary means  of  locomotion,  so  that  in  emergency  cases  it  may 
mean  the  saving  of  a  life.  One  New  York  physician  recently 
put  an  electric  cab  to  a  most  extraordinary  use.  His  patient 
had  a  broken  arm,  and  he  wished  to  photograph  the  fracture 
with  Rontgen  rays,  but  there  was  no  source  of  electricity 
available  in  the  residence  of  the  patient.  So  he  made  a  con- 
nection with  the  battery  in  his  cab,  which  stood  at  the  door ;  the 
rays  were  promptly  applied,  and  the  injury  was  located. 

While  the  electric  vehicle  has  been  winning  plaudits  for  its 
work  in  the  cities,  where  pavements  are  smooth  and  hard,  the 
gasoline  vehicle  has  been  equally  successful  both  in  the  city 


16  ACHIEVEMENTS  IN  SCIENCE 

and  in  the  country.  For  ordinary  use  the  gasoline-propelled 
vehicle  has  many  important  advantages.  It  is  much  lighter 
than  the  electric  vehicle ;  it  requires  no  charging  station,  gaso- 
line being  obtainable  at  every  cross-roads  store;  and  it  is 
moderately  cheap.  All  of  the  famous  long-distance  races  and 
rides  in  Europe  have  been  made  in  gasoline  vehicles.  On  the 
other  hand,  most  of  the  gasoline  vehicles  are  subject  to  slight 
vibrations  due  to  the  motor,  and  it  is  almost  impossible  to  do 
away  entirely  with  the  unpleasant  odors  of  burnt  gases.  Gaso- 
line vehicles  are  never  self-starting,  it  being  necessary  to  give 
the  piston  one  turn  by  hand.  In  general,  also,  they  are  not  as 
simple  of  management  as  the  electric  vehicle ;  there  is  more 
machinery  to  understand  and  to  operate,  and  more  care  is  neces- 
sary to  keep  it  in  order.  But  when  once  the  details  are  mas- 
tered, the  traveler  can  go  almost  anywhere  on  earth  with  his 
gasoline  carriage :  up  hill  and  down,  over  the  roughest  roads, 
through  mud  and  snow,  a  law  unto  himself.  He  can  make 
almost  any  speed  he  chooses. 

The  power  principle  of  the  gasoline  vehicle  is  very  simple. 
It  is  a  well-known  fact  that  when  gasoline  is  mixed  with  air  in 
proper  proportions  and  ignited,  it  explodes  violently.  By  ad- 
mitting this  mixture  at  the  end  or  head  of  the  engine  cylinder, 
and  exploding  it  at  the  proper  moment,  the  piston  is  driven 
violently  forward,  and  then,  by  the  action  of  the  fly-wheel  or 
an  equivalent  device,  it  is  forced  back  again,  and  the  motor  is 
kept  in  motion.  Most  gasoline  engines  are  of  what  is  known 
as  the  four-cycle  variety.  During  the  first  impulse  of  the 
piston  the  vapor  is  drawn  into  the  end  of  the  cylinder,  during 
the  second  it  is  compressed  by  the  return  of  the  piston,  in  the 
third  it  is  exploded,  and  in  the  fourth  the  products  of  the  com- 
bustion are  driven  out,  and  the  end  of  the  cylinder  is  ready  for 
another  charge.  The  explosion  of  the  gas  is  produced  in  the 
most  approved  motors  by  means  of  an  electric  spark,  there 
being  no  fire  anywhere  connected  with  the  machine.  Owing 
to  the  constant  compression  of  the  gases  and  the  succeeding 
explosions,  a  gasoline  motor  becomes  highly  heated,  and  in 
order  to  maintain  a  normal  temperature,  it  must  be  provided 
with  a  jacket  of  cold  water,  or  a  peculiar  ribbed  arrangement  of 

c- 


MODES  OF  TRAVELING  17 

iron  for  increasing  the  radiating  surface.  A  vast  number  of 
ingenious  devices  are  used  for  making  all  of  these  processes  as 
simple  as  possible.  One  motor  is  so  arranged  that  no  igniter 
is  necessary,  the  gas  being  compressed  in  the  cylinder  to  such 
a  degree  that  it  explodes  of  its  own  heat,  thereby  doing  away 
entirely  with  electricity  or  any  other  sparking  device.  In 
France,  most  of  the  gasoline  vehicles  are  still  provided  with 
what  are  known  as  "  carburetters,"  or  small  chambers  where 
the  gas  and  air  are  mixed  in  the  proper  proportions  and  heated 
before  they  are  driven  into  the  cylinder.  In  this  country,  car- 
buretters have  been  largely  done  away  with,  the  gas  being 
mixed  as  it  passes  into  the  cylinder. 

Every  driver  of  a  gasoline  vehicle  must  know  these  general 
facts  about  the  mechanism  of  his  motor.  He  must  know  how 
to  fill  the  gasoline  and  water  tanks,  how  to  replenish  or  regu- 
late the  battery  which  ignites  the  gas,  and  he  must  understand 
the  ordinary  processes  of  cleaning  and  oiling  machinery. 
When  he  is  ready  to  start,  he  must  connect  up  the  sparking 
device  and  turn  the  wheel  controlling  the  piston  until  the  ex- 
plosions begin.  After  that,  he  must  see  that  the  valves  which 
admit  the  air  and  the  gas  are  carefully  adjusted,  so  that  the 
mixture  is  admitted  to  the  cylinder  in  the  proper  proportions, 
and  then  he  is  ready  to  go  ahead,  steering  and  controlling  his 
engine  by  means  of  levers,  and  operating  the  brake  and  gong 
with  his  feet.  All  gasoline  vehicles  are  provided  with  numer- 
ous means  of  stopping,  besides  the  ordinary  use  of  the  brake, 
so  that  there  is  practically  no  possible  danger  of  a  runaway. 
The  Duryea  vehicle,  for  instance,  has  no  fewer  than  five  differ- 
ent means  of  turning  off  the  power  of  the  motor,  all  within 
convenient  reach.  The  secretary  of  the  company  that  manu- 
factures this  vehicle  said  he  had  often  stopped  his  carryall 
within  twenty  feet,  when  going  at  a  speed  of  twenty  miles  an 
hour,  without  great  inconvenience  to  the  passengers.  By  a 
clever  arrangement  for  changing  gearings,  the  gasoline  vehicle 
can  be  made  to  ascend  almost  any  hill,  and  it  can  be  turned  in 
half  the  space  necessary  for  a  horse  vehicle. 

It  is  astonishing  how  little  fuel  it  takes  to  run  a  gasoline 
vehicle.  One  manufacturer  showed  a  phaeton  weighing  seven 
2 


18  ACHIEVEMENTS  IN  SCIENCE 

hundred  pounds  which  he  said  would  run  one  hundred  miles  on 
five  gallons  of  gasoline,  a  bare  half-dollar's  worth.  A  tricycle 
manufactured  by  the  same  company,  weighing  one  hundred 
and  fifty  pounds,  will  run  eighty  miles  on  three  pints  of  gaso- 
line. 

Gasoline  vehicles  vary  in  cost  over  an  even  wider  range 
than  electrical  vehicles.  A  tricycle  can  be  obtained  as  low  as 
$350,  while  an  omnibus  may  cost  into  the  thousands.  A  first- 
class  road  carriage  built  with  all  the  latest  improvements  and 
highly  serviceable  in  every  respect,  can  be  obtained  for  $1,000. 
At  this  price,  the  manufacturers  assert  that  gasoline  power  is 
much  cheaper  than  horse-power.  One  motor-vehicle  expert 
has  made  some  interesting  comparisons,  based  on  an  average 
daily  run  of  twenty-five  miles  for  five  years — more  than  the 
maximum  endurance  of  a  first-class  horse.  His  estimates  rep- 
resent ordinary  city  conditions,  and  rate  the  cost  of  the  gaso- 
line used  at  one-half  cent  a  mile : 

GASOLINE  MOTOR   VEHICLE. 

Original  cost  of  vehicle, $1,000.00 

Cost  of  operation,  i  cent  per  mile,  25  miles  per 

day 

New  sets  of  tires  during  five  years, 
Repairs  on  motor  and  vehicle, 
Painting  vehicle  four  times,      .... 
Storing  and  care  of  vehicles,  $100.00  per  year, 

$2,306.50 

HORSE  AND   VEHICLE. 

Original  cost  of  horse,  harness,  and  vehicle,     .  $500.00 
Cost  of  keeping  horse,  $30.00  per  month,  five 

years, 1,800.00 

Repairs  on  vehicle,  including  rubber  tires,       .  150.00 

Shoeing  horse,  $3.00  a  month,  five  years,         .  180.00 

Repairs  on  harness,  $10.00  per  year,          .        .  50.00 

Painting  vehicle  four  times,       ....  100.00 


$2,780.00 

"At  the  end  of  five  years,"  explained  this  expert,  "the 
motor  vehicle  should  be  in  reasonably  good  condition,  while  the 


MODES  OF  TRAVELING  19 

value  of  the  horse  and  carriage  would  be  doubtful.  There  is 
always  the  possibility  that  at  least  one  of  the  horses  may  die  in 
five  years,  while  the  motor  vehicle  can  always  be  repaired  at  a 
comparatively  nominal  cost.  But  even  assuming  that  the  rela- 
tive value  of  each  is  the  same  at  the  end  of  five  years,  the  cost 
of  actual  maintenance  during  that  period  would  be  $1,306.50 
for  the  motor  vehicle  and  $2,280  for  the  horse  and  vehicle,  or 
$973-5°  m  favor  of  the  motor  vehicle.  This  comparison  is 
really  doing  more  than  justice  to  the  horse,  because  a  motor 
vehicle  can  do  the  work  of  three  horses  without  injury." 

Steam  has  been  successfully  applied  to  the  heavier  grades 
of  vehicles,  notably  trucks,  fire-engines,  and  omnibuses;  and 
two  or  three  American  manufacturers  have  gone  still  further, 
and  have  produced  light  and  natty  steam  buggies  and  runabouts, 
and  even  steam  tricycles.  Steam  vehicles  are  easily  started 
and  stopped,  and  fuel  and  water  are  always  readily  obtainable ; 
but  there  is  also  the  disadvantage  of  a  slight  cloud  of  steam 
escaping  from  the  exhaust,  accompanied  by  more  or  less  noise. 
Moreover,  in  many  states  there  are  regulations  (mostly  unen- 
forced  in  the  case  of  motor  vehicles)  against  the  operation  of 
steam-engines  except  by  licensed  engineers,  and  it  is  probable 
that  steam  automobiles  will  not  be  widely  accepted  for  pleasure 
purposes  until  the  inventors  have  succeeded  in  producing  auto- 
matic engines. 

Much  has  been  said  as  to  the  use  of  compressed  air  for 
heavy  trucks,  and  several  immense  corporations  have  been 
organized  to  promote  its  use.  The  air  is  compressed  at  a  cen- 
tral station,  and  admitted  to  heavy  steel  storage  bottles,  or 
tubes,  connected  with  the  truck  and  used  much  like  steam. 
The  main  difficulty  in  the  process  has  been  the  sudden  cooling 
of  the  machinery  when  the  air  is  released  from  pressure  and 
begins  to  take  up  heat.  Often  the  pipes  and  valves  are  frozen 
solid.  To  deal  with  this  problem,  a  jacket  of  water  heated  by 
a  gasoline  flame  is  provided  for  "  reheating  "  the  air,  a  difficult 
and  cumbersome  process.  Owing  to  the  weight  of  the  steel 
tubes,  the  compressed-air  vehicles  are  enormously  heavy,  and, 
like  electric  vehicles,  they  must  return  to  some  charging  sta- 
tion, after  traveling  twenty  or  thirty  miles,  for  a  new  supply 


20  ACHIEVEMENTS  IN  SCIENCE 

of  power.  And  yet  both  inventors  and  financial  promoters  are 
sanguine  of  ultimate  success  with  them. 

A  Chicago  inventor  has  been  building  a  truck  in  which  he 
combines  gasoline  and  electrical  power.  An  eight-horse-power 
gasoline  engine  situated  over  the  front  axle  drives  an  electrical 
generator,  which  in  turn  feeds  a  small  storage  battery,  thus 
producing  power  as  the  vehicle  moves,  and  rendering  it  entirely 
independent  of  a  charging  station.  One  man  can  handle  the 
entire  truck,  and  it  is  said  that  the  cost  of  operation  will  not 
exceed  eighty  cents  a  day.  The  main  objection  to  this  system, 
as  with  compressed  air,  is  the  enormous  weight  of  the  vehicle, 
which  is  upwards  of  9,000  pounds.  The  truck  has  a  carrying 
capacity  of  eight  tons,  making  a  total  of  25,000  pounds.  Such 
a  vehicle  presents  problems  which  modern  pavement  builders 
have  yet  to  solve. 

But  the  time  is  certainly  coming,  and  that  soon,  when  all 
heavy  loads  must  be  drawn  by  automobiles.  Recent  English 
experiments,  already  mentioned,  have  established  the  feasibility 
of  the  auto-truck  even  in  its  present  experimental  stage,  and 
the  inventor  needs  no  further  encouragement  to  prosecute  his 
work.  It  is  hardly  possible  to  conceive  the  appearance  of  a 
crowded  wholesale  street  in  the  day  of  the  automatic  vehicle. 
In  the  first  place,  it  will  be  almost  as  quiet  as  a  country  lane — 
all  the  crash  of  horses'  hoofs  and  the  rumble  of  steel  tires  will 
be  gone.  The  vehicles  will  be  fewer  and  heavier,  although 
much  shorter  than  the  present  truck  and  span,  so  that  the 
streets  will  appear  much  less  crowded.  And  with  larger  loads, 
more  room,  and  less  necessary  attention,  more  business  can  be 
done,  and  at  less  expense. 

A  New  York  manufacturer  produces  an  odd  variation  of 
the  motor  vehicle  in  what  he  calls  a  "  mechanical  horse."  It  is 
a  one-  or  three-wheeled  equipment  provided  with  an  electric 
motor,  and  it  can  be  attached  to  almost  any  kind  of  carriage  or 
wagon  body  and  used  for  propulsion  like  a  veritable  mechani- 
cal horse. 

As  to  what  form  the  future  motor  vehicle  will  take  there  is 
the  widest  diversity  of  opinion.  Business  clashes  with  art. 
Horse  carriages  are  built  high  so  that  the  driver  can  see  over 


MODES  OF  TRAVELING  fct 

the  horse  and  avoid  the  dust.  The  first  motor  vehicles  were 
merely  "  carriages-without-the-horse,"  and  some  of  them  looked 
clumsy  and  odd  enough,  "  bobbed  off  in  front,"  as  one  enthu- 
siast told  me. 

The  utility  of  the  automobile  in  any  city  is  in  direct  propor- 
tion to  the  condition  of  its  streets.  It  is  hardly  surprising  that 
manufacturers  are  receiving  the  greatest  number  of  inquiries 
from  cities  like  Buffalo  and  Detroit,  where  the  pavements  are 
good,  and  from  California  and  part  of  New  England.  The 
automobile  has  had  such  acceptance  in  France  because  the 
highways  are  all  as  smooth  as  park  paths.  Bicycling  already 
has  had  a  profound  influence  in  spurring  the  road-makers,  and 
the  introduction  of  the  motor  vehicle  will  be  still  more  effec- 
tive. Colonel  Waring  estimated  that  two-thirds  of  all  street 
dirt  is  traceable  to  the  horse.  At  present  it  costs  New  York 
nearly  $3,000,000  a  year  to  clean  its  streets.  With  new  pave- 
ments such  as  the  new  soft-tired  vehicles  and  the  absence  of 
pounding  hoofs  would  make  possible,  street  cleaning  would  be- 
come a  minor  problem.  And  new  asphalt  pavement  could  be 
put  down  at  the  rate  of  forty  miles  a  year  for  what  New  York 
now  spends  for  half  cleaning  its  streets. 

As  yet  American  law-makers  have  hardly  touched  on  the 
subject  of  motor  vehicles.  In  New  York,  if  drivers  keep  out 
of  Central  Park,  display  a  light,  ring  a  gong,  and  do  not  speed 
faster  than  eight  miles  an  hour,  no  one  interferes  with  them. 
Similar  regulations  prevail  in  Boston,  and  in  other  American 
cities.  In  Brooklyn  the  parks  are  free.  France  and  England, 
on  the  other  hand,  hedge  in  automobile  drivers  with  all  manner 
of  rules  and  regulations,  and  require  them  to  be  officially 
licensed.  In  France,  by  recently  promulgated  articles,  every 
type  of  vehicle  employed  must  offer  complete  conditions  of 
security  in  its  mechanism,  its  steering  gear,  and  its  brakes. 
The  constructors  of  automobiles  must  have  the  specifications 
of  each  type  of  machine  verified  by  the  Service  des  Mines. 
After  a  certificate  of  such  verification  has  been  granted,  the 
constructor  is  at  liberty  to  manufacture  an  unlimited  number 
of  vehicles.  Each  vehicle  must  bear  the  name  of  the  construc- 
tor, an  indication  of  the  type  of  machine,  the  number  of  the 


22  ACHIEVEMENTS  IN  SCIENCE 

vehicle  in  that  type,  and  the  name  and  domicile  of  its  owner. 
No  one  may  drive  an  automobile  who  is  not  the  holder  of  a 
certificate  of  capacity  signed  by  the  prefect  of  the  department 
in  which  he  resides. 

The  regulations  are  most  explicit  on  the  important  question 
of  speed.  In  narrow  or  crowded  thoroughfares  the  speed  must 
be  reduced  to  walking  pace.  In  no  case  may  the  speed  exceed 
eighteen  and  one-half  miles  an  hour  in  the  open  country,  or 
twelve  and  one-half  miles  an  hour  when  passing  houses.  Rela- 
tive to  signals,  the  regulations  say  that  "  the  approach  of  an 
automobile  must,  if  necessary,  be  signaled  by  means  of  a  trum- 
pet." Each  automobile  must  be  provided  with  two  lamps,  one 
white,  the  other  green.  Racing  is  allowed,  provided  an  authori- 
zation is  obtained  from  the  prefect  and  the  mayors  are  warned. 
In  racing,  the  speed  of  eighteen  and  one-half  miles  an  hour 
may  be  exceeded  in  the  open  country,  but  when  passing  houses, 
the  maximum  of  twelve  and  one-half  miles  must  not  be  ex- 
ceeded. 

One  curious  difficulty  in  connection  with  the  new  vehicle  is 
the  difficulty  of  finding  suitable  English  names  to  designate  it 
and  its  driver.  The  French,  with  characteristic  readiness  in 
getting  settled  names  for  things,  have,  as  already  noted,  for- 
mally adopted  the  word  "automobile,"  for  the  vehicle  and 
"  chauffeur  "  (stoker)  for  the  driver.  But  we  of  the  English 
tongue  are  slower.  At  least  a  dozen  names  have  been  used  to 
a  greater  or  less  extent,  such  as  "motor  carriage,"  "auto-car- 
riage," and  "  horseless  carriage."  In  England,  "  self-propeller  " 
is  popular  and  so  is  "auto-car,"  the  latter  being  apparently  the 
favored  designation.  "  Motor  vehicle  "  seems  to  be  the  more 
generally  accepted  name  in  this  country.  But  whatever  it  is, 
or  is  yet  to  be  called,  the  thing  itself  must  now  be  rated  an 
accepted  and  established  appliance  of  every-day  life. 

Since  this  article  was  written,  there  have  been  American 
records  of  seventy,  eighty,  and  eighty-five  miles  an  hour,  in 
speed  tests  made  on  prepared  tracks  and  on  country  roads. 
There  have  also  been  a  number  of  fatalities  among  driving  par- 
ties and  persons  riding  or  walking  on  the  streets  and  roads. 


MODES  OF  TRAVELING 


The  Flying  Machine 

By  RAY  STANNARD  BAKER 

T^LYING-MACHINE  inventors  and  enthusiasts  may  be 
JL  divided  into  two  great  classes,  each  of  which  is  certain 
that  it  has  discovered  the  only  straight  and  narrow  path  to 
aerial  navigation.  Those  who  belong  to  the  first  of  these 
classes  place  their  faith  in  the  steerable  or  dirigible  balloon ; 
they  secure  their  lifting  power  with  gas,  and  seek  to  control 
the  direction  of  flight  by  various  contrivances  of  wings  and 
screw  propellers.  They  are  air  soarers.  Those  of  the  second 
class  go  to  the  bird  for  their  model.  The  bird,  they  assert,  is 
nature's  first  and  best  flying  machine ;  and  if  a  bird,  which  is 
nearly  a  thousand  times  as  heavy  as  the  air  it  displaces,  can 
soar  for  hours  aloft  without  tiring,  why  shouldn't  a  man  do  the 
same,  provided  he  can  build  the  proper  mechanism  ?  Conse- 
quently these  inventors,  who  have  given  the  subject  of  bird 
flight  long  and  serious  attention,  discard  the  balloon  system 
with  something  of  disdain,  and  plan  their  machines  after  the 
perfect  model  of  a  bird's  wing. 

Both  of  these  methods  have  been  thoroughly  tested,  and, 
what  is  more,  with  astonishing  success,  considering  the  difficul- 
ties which  have  had  to  be  overcome.  Balloon  flying  machines 
have  really  been  steered,  not  to  the  limits  of  success,  but  far 
enough  to  demonstrate  that  the  feat  can  be  accomplished.  On 
the  other  hand,  a  soaring  or  aeroplane  machine  has  been  con- 
structed and  actually  made  to  fly  for  considerable  distances ; 
and  yet  more  curious  and  interesting,  a  number  of  daring  in- 

23 


24  ACHIEVEMENTS  IN  SCIENCE 

ventors  have  constructed  real  wings  with  which  they  have 
soared  with  success  from  hill-tops  and  high  walls. 

Both  of  these  methods  are,  therefore,  worthy  of  careful  con- 
sideration, although  I  now  take  up  only  flying  machines  proper 
— the  aeroplanes  and  bird-like  contrivances — the  balloon  ma- 
chines or  air  floaters  coming  more  properly  under  the  impor- 
tant subject  of  ballooning. 

I  suppose  more  inventors  have  been  fascinated  with  the 
idea  of  building  a  machine  that  would  fly  than  with  almost  any 
other  single  subject,  perpetual  motion  possibly  excepted. 
Nearly  every  town  has  its  flying-machine  enthusiaast,  and  the 
Patent  Office  at  Washington  is  busy  constantly  with  curious 
designs  for  winged  mechanisms ;  and  yet  the  perfect  machine, 
the  machine  which  will  one  day  supplant  the  steamship,  bank- 
rupt the  railroad,  and  annihilate  space,  is  yet  to  be  invented. 
And  invented  it  positively  will  be,  for  mathematicians  have 
demonstrated  its  possibility  by  unerring  figures,  and  it  only  re- 
mains for  the  clever  mechanician  to  build  the  necessary 
machinery. 

Probably  no  American  inventor  of  flying  machines  is  so 
well  known  for  his  experiments  as  Professor  S.  P.  Langley,  the 
distinguished  secretary  of  the  Smithsonian  Institution  at 
Washington.  He  has  built  a  machine  with  wings,  driven  by  a 
steam-engine,  and  wholly  without  gas  or  other  lifting  power 
beyond  its  own  internal  energy.  And  this  machine,  to  which 
has  been  given  the  name  aerodrome  (air  runner),  actually  flies 
for  considerable  distances.  So  successful  were  Professor 
Langley's  early  tests,  that  the  United  States  Government 
recently  made  a  considerable  appropriation  to  enable  him  to 
carry  forward  his  experiments  in  the  hope  of  finally  securing  a 
practical  flying  machine. 

The  invention  of  the  aerodrome  was  the  result  of  long  years 
of  persevering  and  exacting  labor,  with  so  many  disappoint- 
ments and  setbacks  that  one  cannot  help  admiring  the  aston- 
ishing patience  which  kept  hope  alive  to  the  end.  Early  in  his 
experiments,  Professor  Langley  had  proved  positively,  by 
mathematical  calculations,  that  a  machine  could  be  made  to  fly, 
provided  its  structure  were  light  enough  and  the  actuating 


MODES  OF  TRAVELING  25 

power  great  enough.  Therefore  he  was  not  in  pursuit  of  a 
mere  will-o'-the-wisp.  It  was  a  mechanical  difficulty  which  he 
had  to  surmount,  and  he  surmounted  it. 

Professor  Langley  made  his  first  experiments  more  than 
twelve  years  ago  at  Allegheny,  Pennsylvania.  He  began,  not 
by  building  a  flying  machine,  but  with  a  thorough  investigation 
into  the  theory  of  the  flight  of  birds,  in  order  to  find  out  how 
much  power  was  needed  to  sustain  a  surface  of  given  weight 
by  means  of  its  motion  through  the  air.  For  this  purpose  he 
built  a  very  large  " whirling  table" — a  device  having  an  arm 
which  swept  around  a  central  pivot,  the  outer  end  of  which 
could  be  given  a  velocity  of  seventy  miles  an  hour.  Various 
objects  were  hung  at  the  end  of  the  arm  and  dragged  through 
the  air,  until  its  resistance  supported  them  just  as  a  kite  is  sup- 
ported by  the  wind.  A  plate  of  brass  weighing  one  pound,  for 
instance,  was  hung  from  the  end  of  the  arm  by  a  spring,  which 
was  drawn  out  until  it  registered  a  pound  weight  when  the  arm 
was  still.  When  the  arm  was  in  motion,  it  might  be  expected 
that,  as  it  was  drawn  faster,  the  pull  would  be  greater;  but 
Professor  Langley's  observations,  strangely  enough,  showed 
just  the  contrary,  for  under  these  circumstances  the  spring 
contracted  until  it  registered  less  than  an  ounce.  With  the 
speed  increased  to  that  of  a  bird  in  flight,  the  brass  plate 
seemed  to  float  on  the  air.  Preliminary  experiments  of  this 
nature  were  continued  for  three  long  years,  and  Professor  Lang- 
ley  formed  the  general  conclusion  that  by  simply  moving  any 
given  weight  in  plate  form  fast  enough  in  a  horizontal  path 
through  the  air  it  was  possible  to  sustain  it  with  very  little 
power.  It  was  proved  that,  if  horizontal  flight  without  friction 
could  be  insured,  two  hundred  pounds  of  plates  could  be  moved 
through  the  air  and  sustained  upon  it  at  the  speed  of  an  express 
train,  with  the  expenditure  of  only  one  horse-power,  and  that, 
of  course,  without  using  any  gas  to  lighten  the  weight. 

Every  boy  who  has  skated  knows  that  when  the  ice  is  very 
thin  he  must  skate  rapidly,  else  he  may  break  through.  In  the 
same  way,  a  stone  may  be  skipped  over  the  water  for  consider- 
able distances.  If  it  stops  in  any  one  place  it  sinks  instantly. 
In  exactly  the  same  way,  the  plate  of  brass,  if  left  in  any  one 


26  ACHIEVEMENTS  IN  SCIENCE 

place  in  the  air,  would  instantly  drop  to  the  earth;  but  if 
driven  swiftly  forward  in  a  horizontal  direction  it  rests  only  an 
instant  in  any  particular  place,  and  the  air  under  it  at  any 
single  moment  does  not  have  time  to  give  way,  so  to  speak,  be- 
fore it  has  passed  over  a  new  area  of  air.  In  fact,  Professor 
Langley  came  to  the  conclusion  that  flight  was  theoretically 
possible  with  engines  he  could  then  build,  since  he  was  satisfied 
that  engines  could  be  constructed  to  weigh  less  than  twenty 
pounds  to  the  horse-power,  and  that  one  horse-power  would 
support  two  hundred  pounds  if  the  flight  was  horizontal. 

That  was  the  beginning  of  the  aerodrome.  Professor  Lang- 
ley  had  worked  out  its  theory,  and  now  came  the  much  more 
difficult  task  of  building  a  machine  in  which  theory  should  take 
form  in  fact.  In  the  first  place,  there  was  the  vast  problem  of 
getting  an  engine  light  enough  to  do  the  work.  A  few  years 
ago  an  engine  that  developed  one  horse-power  weighed  nearly 
as  much  as  an  actual  horse.  Professor  Langley  wished  to 
make  one  weighing  only  twenty  pounds,  a  feat  never  before 
accomplished.  And  then,  having  made  his  engine,  how  was  he 
to  apply  the  power  to  obtain  horizontal  speed  ?  Should  it  be 
by  flapping  wings  like  a  bird,  or  by  a  screw  propeller  like  a 
ship  ?  This  question  led  him  into  a  close  study  of  the  bird 
compared  with  the  man.  He  found  how  wonderfully  the  two 
were  alike  in  bony  formation,  how  curiously  the  skeleton  of  a 
bird's  wing  was  like  a  man's  arm,  and  yet  he  finally  decided 
that  flapping  wings  would  not  make  the  best  propeller  for  his 
machine.  Men  have  not  adopted  machinery  legs  for  swift  loco- 
motion, although  legs  are  nature's  models,  but  they  have 
rather  constructed  wheels — contrivances  which  practically  do 
not  exist  in  nature.  Therefore,  while  Professor  Langley  admits 
that  successful  flying  machines  may  one  day  be  made  with  flap- 
ping wings,  he  began  his  experiments  with  the  screw  propeller. 

There  were  three  great  problems  in  building  the  flying 
machine.  First,  an  engine  and  boilers  light  enough  and  at  the 
same  time  of  sufficient  power.  Second,  a  structure  which 
should  be  rigid  and  very  light.  Third,  the  enormously  difficult 
problem  of  properly  balancing  the  machine,  which,  Professor 
Langley  says,  "  took  years  to  acquire." 


MODES  OF  TRAVELING  27 

For  his  propelling  power  he  tried  compressed  air,  gas,  elec- 
tricity, carbonic-acid  gas,  and  many  other  sources  of  energy, 
but  he  finally  settled  on  the  steam-engine,  and  he  succeeded, 
after  all  manner  of  difficulties,  in  building  a  mechanism  light 
enough.  He  says  in  regard  to  this  part  of  the  work: 

"The  chief  obstacle  proved  to  be  not  with  the  engines, 
which  were  made  surprisingly  light  after  sufficient  experiment. 
The  great  difficulty  was  to  make  a  boiler,  of  almost  no  weight, 
which  would  give  steam  enough,  and  this  was  a  most  wearying 
one.  There  must  be  also  a  certain  amount  of  wing  surface, 
and  large  wings  weighed  prohibitively ;  there  must  be  a  frame 
to  hold  all  together,  and  the  frame,  if  made  strong  enough, 
must  yet  weigh  so  little  that  it  seemed  impossible  to  make  it. 
These  were  the  difficulties  that  I  still  found  myself  in  after 
two  years  of  experiment,  and  it  seemed  at  this  stage  again  as 
if  it  must,  after  all,  be  given  up  as  a  hopeless  task,  for  some- 
how the  thing  had  to  be  built  stronger  and  lighter  yet.  Now, 
in  all  ordinary  construction,  as  in  building  a  steamboat  or  a 
house,  engineers  have  what  they  call  a  factor  of  safety.  An 
iron  column,  for  instance,  will  be  made  strong  enough  to  hold 
five  or  ten  times  the  weight  that  is  ever  going  to  be  put  upon 
it ;  but  if  we  try  anything  of  the  kind  here,  the  construction 
will  be  too  heavy  to  fly.  Everything  in  the  work  has  got  to  be 
so  light  as  to  be  on  the  edge  of  breaking  down  and  disaster, 
and  when  the  breakdown  comes,  all  we  can  do  is  to  find  what 
is  the  weakest  part  and  make  that  part  stronger;  and  in  this 
way  work  went  on,  week  by  week  and  month  by  month,  con- 
stantly altering  the  form  of  construction  so  as  to  strengthen 
the  weakest  parts,  until,  to  abridge  a  story  which  extended  over 
years,  it  was  finally  brought  nearly  to  the  shape  it  is  now, 
where  the  completed  mechanism,  furnishing  over  a  horse-power, 
weighs  collectively  something  less  than  seven  pounds.  This 
does  not  include  water,  the  amount  of  which  depends  on  how 
long  we  are  to  run ;  but  the  whole  thing,  as  now  constructed, 
boiler,  fire-grate,  and  all  that  is  required  to  turn  out  an  actual 
horse-power  and  more,  weighs  something  less  than  one  one- 
hundredth  part  of  what  the  horse  himself  does." 

From  this  it  will  be  seen  what  tremendous  difficulties  had 


28  ACHIEVEMENTS  IN  SCIENCE 

to  be  met  and  solved,  and  yet  the  machine  could  not  fly  inde- 
pendently, although  the  mechanical  power  was  there. 

Professor  Langley  established  an  experimental  station  in 
the  Potomac  River,  some  miles  below  Washington.  An  old 
scow  was  obtained,  and  a  platform  about  twenty  feet  high  was 
built  on  top  of  it.  To  this  spot,  in  1893,  the  machine  was 
taken,  and  here  failure  followed  failure ;  the  machine  would  not 
fly  properly,  and  yet  every  failure,  costly  as  it  might  be  in 
time  and  money,  brought  some  additional  experience.  Pro- 
fessor Langley  found  out  that  the  aerodrome  must  begin  to  fly 
against  the  wind,  just  in  the  opposite  way  from  a  ship.  He 
found  that  he  must  get  up  full  speed  in  his  engine  before  the 
machine  was  allowed  to  go,  in  the  same  way  that  a  soaring  bird 
must  make  an  initial  run  on  the  ground  before  it  can  mount 
into  the  air,  and  this  was,  for  various  reasons,  a  difficult  prob- 
lem. And  then  there  was  the  balancing. 

"  If  the  reader  will  look  at  the  hawk  or  any  soaring  bird," 
says  Professor  Langley,  "  he  will  see  that  as  it  sails  through 
the  air  without  flapping  the  wing,  there  are  hardly  two  consecu- 
tive seconds  of  its  flight  in  which  it  is  not  swaying  a  little  from 
side  to  side,  lifting  one  wing  or  the  other,  or  turning  in  a  way 
that  suggests  an  acrobat  on  a  tight-rope,  only  that  the  bird  uses 
its  widely  outstretched  wings  in  place  of  the  pole." 

It  must  be  remembered  that  air  currents,  unlike  the  Gulf 
Stream,  do  not  flow  steadily  in  one  direction.  They  are  for- 
ever changing  and  shifting,  now  fast,  now  slow,  with  some- 
thing of  the  commotion  and  restlessness  of  the  rapids  below 
Niagara. 

All  of  these  things  Professor  Langley  had  to  meet  as  a  part 
of  the  difficult  balancing  problem,  and  it  is  hardly  surprising 
that  nearly  three  years  passed  before  the  machine  was  actually 
made  to  fly- — on  May  6,  1896. 

"  I  had  journeyed,  perhaps  for  the  twentieth  time,"  says 
Professor  Langley,  "to  the  distant  river  station,  and  recom- 
menced the  weary  routine  of  another  launch,  with  very  moder- 
ate expectation  indeed;  and  when,  on  that,  to  me,  memorable 
afternoon  the  signal  was  given  and  the  aerodrome  sprang  into 
the  air,  I  watched  it  from  the  shore  with  hardly  a  hope  that 


MODES   OF  TRAVELING  29 

the  long  series  of  accidents  had  come  to  a  close.  And  yet  it 
had,  and  for  the  first  time  the  aerodrome  swept  continuously 
through  the  air  like  a  living  thing,  and  as  second  after  second 
passed  on  the  face  of  the  stop-watch,  until  a  minute  had  gone 
by,  and  it  still  flew  on,  and  as  I  heard  the  cheering  of  the  few 
spectators,  I  felt  that  something  had  been  accomplished  at  last ; 
for  never  in  any  part  of  the  world,  or  in  any  period,  had  any 
machine  of  man's  construction  sustained  itself  in  the  air  before 
for  even  half  of  this  brief  time.  Still  the  aerodrome  went  on 
in  a  rising  course  until,  at  the  end  of  a  minute  and  a  half  (for 
which  time  only  it  was  provided  with  fuel  and  water),  it  had 
accomplished  a  little  over  half  a  mile,  and  now  it  settled,  rather 
than  fell,  into  the  river,  with  a  gentle  descent.  It  was  immedi- 
ately taken  out  and  flown  again  with  equal  success,  nor  was 
there  anything  to  indicate  that  it  might  not  have  flown  indefi- 
nitely, except  for  the  limit  put  upon  it." 

Only  a  brief  description  of  Professor  Langley's  machine  can 
here  be  given.  It  has  two  pairs  of  wings,  each  slightly  curved, 
attached  to  a  long  steel  rod  from  which  hang  the  boilers, 
engines,  and  other  machinery,  and  the  propeller  wheels.  The 
hub  itself  is  formed  of  steel  tubing ;  in  front  there  is  a  little 
conical  float  to  keep  the  machine  from  sinking,  should  it  fall  in 
the  water.  The  boiler  weighs  a  little  over  five  pounds,  while 
the  engine,  which  gives  one  and  one-half  horse-power,  weighs 
only  twenty-six  ounces.  The  rudder  is  arranged  for  steering  in 
four  directions — up,  down,  to  the  right,  and  to  the  left,  and  all 
automatically. 

The  width  of  the  wings  from  tip  to  tip  is  between  twelve 
and  thirteen  feet,  and  the  length  of  the  whole  about  sixteen 
feet.  The  weight  is  nearly  thirty  pounds,  of  which  about  one- 
fourth  is  the  machinery. 

So  much  for  Professor  Langley's  aerodrome,  the  first  and 
most  wonderful  of  machines  of  its  kind.  Hiram  Maxim,  the 
famous  inventor  of  the  Maxim  gun,  has  experimented  on  a 
colossal  affair  of  aeroplanes  to  carry  three  men — and  she  ran 
swiftly  when  her  wheels  rested  firmly  on  the  wide  rails  of  her 
little  railroad,  but  her  inventor  never  has  ventured  to  lift  her 
free  in  the  air.  These  two  inventions,  Langley's  and  Maxim's, 


30  ACHIEVEMENTS  IN  SCIENCE 

have  been  the  greatest  efforts  toward  the  utilization  of  the 
soaring  plane. 

The  possibility  of  using  wings  for  flight  is  one  of  the  very 
oldest  of  mechanical  ideas.  It  is  so  easy  to  say,  "  A  bird  flies ; 
why  shouldn't  a  man  ? "  and  more  than  one  brilliant  inventor 
has  been  dashed  to  death  trying  to  answer  this  very  question. 
What  boy  hasn't  read  of  the  amusing  adventures  of  Darius 
Green  ?  And  yet  of  late  years,  wonderful  enough,  men  have 
actually  flown  with  wings,  wings  resembling  those  of  a  soaring 
bird.  Only  a  year  or  two  ago  Lilienthal,  the  famous  "  flying 
man "  of  Berlin,  was  killed  from  a  fall  received  while  he  was 
careering  high  above  the  earth  with  his  great  wings.  Chanute, 
an  American  inventor,  has  flown  successfully  with  wings ;  and 
only  recently  Hargrave,  the  Australian  inventor  of  the  famous 
box-kite,  has  been  making  kite-like  wings  which  he  asserts  will 
solve  the  great  problem  of  practical  aerial  navigation. 

Lilienthal,  the  flying  man,  built  his  wings  after  a  long  and 
close  study  of  the  flight  of  birds.  He  finally  came  to  the  con- 
clusion that  a  bird  is  able  to  sustain  itself  without  apparent 
effort  in  the  air,  and  even  to  soar  against  the  wind,  owing  to 
the  peculiar  curved  surface  of  its  wings.  The  fins  of  many 
fishes  and  the  web  feet  of  aquatic  birds  are  strikingly  analogous 
in  construction.  The  sails  of  a  ship  assume  a  similar  form.  It 
would  be  impossible  to  sail  so  near  the  wind  in  beating  if  the 
instrument  of  propulsion  were  a  rigid  flat  surface.  It  is  the 
effort  of  the  sail  to  get  away  from  the  wind  which  it  gathers  in 
its  ample  bosom  which  drives  the  boat  forward,  almost  in  the 
very  teeth  of  the  breeze.  The  flying  machine  devised  and  used 
by  Herr  Lilienthal  was  designed  rather  for  sailing  than  for 
flying,  in  the  proper  sense  of  the  term ;  or,  as  he  once  said, 
"  for  being  carried  steadily  and  without  danger,  under  the  least 
possible  angle  of  descent,  against  a  moderate  wind,  from  an 
elevated  point  to  the  plain  below."  It  was  made  almost  entirely 
of  closely  woven  muslin,  washed  with  collodion  to  render  it  im- 
pervious to  air,  and  stretched  upon  a  ribbed  frame  of  split  wil- 
low, which  was  found  to  be  the  lightest  and  strongest  material 
for  this  purpose.  Its  main  elements  were  the  arched  wings ;  a 
vertical  rudder,  shaped  like  a  palm-leaf  fan,  which  acted  as  a 


MODES  OF  TRAVELING  31 

vane  in  keeping  the  head  always  towards  the  wind ;  and  a  flat, 
horizontal  rudder,  to  prevent  sudden  changes  in  the  equilibrium. 

The  operator  so  adjusted  the  apparatus  to  his  person  that, 
when  in  the  air,  he  either  rested  on  his  elbows  or  was  seated 
upon  a  narrow  support  near  the  front.  With  the  wings  folded 
behind  him,  he  made  a  short  run  from  some  elevated  point, 
always  against  the  wind,  and  when  he  attained  sufficient 
velocity,  launched  himself  into  the  air  by  a  spring  or  jump,  at 
the  same  time  spreading  the  wings,  which  were  at  once  ex- 
tended to  their  full  breadth,  whereupon  he  sailed  majestically 
along  like  a  gigantic  seagull.  In  this  way  Herr  Lilienthal  often 
accomplished  flights  of  three  hundred  yards  and  more  from  the 
starting-point. 

"  No  one,"  Herr  Lilienthal  once  explained,  "can  realize  how 
substantial  the  air  is  until  he  feels  its  supporting  power  beneath 
him.  It  inspires  confidence  at  once.  With  flat  wings  it  would 
be  almost  impossible  to  guard  against  a  fall.  With  arched 
wings  it  is  possible  to  sail  against  a  moderate  breeze  at  an  angle 
of  not  more  than  six  degrees  to  the  horizon." 

The  principle  is  recognized  in  the  umbrella  form  universally 
adopted  for  the  parachute.  Try  to  run  with  an  open  umbrella 
held  above  the  head  and  slightly  inclined  backward,  and  see 
what  a  lifting  power  it  exerts. 

Lilienthal  spent  many  years  of  toil  on  his  invention,  and 
after  his  final  perfected  wings  were  finished,  it  required  much 
skill  and  strength  to  use  them  successfully,  to  guide  the  direc- 
tion of  flight  by  careful  movements  of  the  arms,  to  go  up  by 
leaning  back,  and  down  by  leaning  forward.  And  at  the  last 
the  inventor  himself  was  hurled  to  his  death,  but  not  until  he 
had  contributed  much  to  the  knowledge  of  aeronautics. 

Mr.  Hargrave  has  contributed  to  scientific  information  a 
very  clear  statement  as  to  why  a  bird  is  able  to  soar  against 
the  wind,  and  he  is  using  his  discoveries  as  the  basis  for  a  new 
invention  in  flying  machines.  Hargrave' s  idea  is  that  the  thick 
forward  part  of  a  bird's  wing  acts  as  an  obstruction,  like  a  dam 
in  a  river,  causing  a  whirlpool  below  the  wing,  which  rolls  with 
great  force  against  the  back  side  of  this  obstruction,  thereby 
forcing  it  forward.  In  other  words,  progress  through  the  air 


32  ACHIEVEMENTS  IN  SCIENCE 

is  caused  by  an  undertow  of  air.  He  suggests,  therefore,  a 
flying  machine  shaped  somewhat  in  the  form  of  a  toboggan 
turned  upside  down.  The  wind,  striking  the  edge  of  the  tobog- 
gan curve  in  front,  creates  a  whirlpool  in  the  inverted  hollow, 
and  propels  the  whole  machine  forward  and  upward,  according 
to  the  way  it  is  steered  by  the  suspended  ballast,  which  deter- 
mines its  angle  of  flight. 

Each  year  the  inventor  presses  closer  to  the  great  secret  of 
human  flight,  each  year  the  mechanic  is  able  to  build  more 
perfect  machinery,  and  the  two,  working  side  by  side,  may  be 
expected  before  many  years  have  passed  to  produce  a  flying 
machine  which  will  be  practically  a  success  as  well  as  an  exper- 
imental success. 

Great  interest  was  stirred  by  the  success  of  a  young  gentle- 
man from  Brazil,  M.  Santos-Dumont,  in  navigating  a  dirigible 
balloon  round  the  Eiffel  tower  in  Paris.  Several  times  he 
demonstrated  the  possibility  of  constructing  machines  large 
enough  to  carry  several  persons  and  follow  a  course  independ- 
ently of  mild  air  currents. 

A  Santos-Dumont  balloon  has  been  tried  at  Coney  Island, 
where  it  was  sailed  for  a  mile  or  so  in  conditions  less  favorable 
than  they  would  have  been  had  the  experiment  not  been  made 
impromptu.  About  the  same  time,  September,  1902,  a  well- 
known  aeronaut  of  London,  Stanley  Spencer,  surprised  every 
one  by  making  a  trip  of  thirty  miles,  unannounced,  from  the 
Crystal  Palace,  by  a  curved  course  over  South  London  to 
Harrow,  without  accident.  He  repeatedly  lowered  his  machine 
to  within  a  few  hundred  feet  of  the  earth,  and  changed  its  di- 
rection and  speed  at  will.  His  balloon  was  oblong,  with  the 
motor  at  the  front  end,  like  the  wings  of  a  dragon-fly. 


MODES  OF  TRAVELING 


What  Keeps   the  Bicycler  Upright? 

By  CHARLES  B.  WARRING 

'T^HERE  is  something  weird,  almost  uncanny,  in  the  noise- 
JL  less  rush  of  the  cyclist,  as  he  comes  into  view,  passes 
by,  and  disappears.  Pedestrians  and  carriages  are  left  behind. 
He  yields  only  to  the  locomotive  and  to  birds.  The  apparent 
ease  and  security  of  his  movement  excite  our  wonder.  We 
have  seen  rope-walkers,  and  most  of  us  have  tried  to  walk  on 
the  top  rail  of  a  fence,  and  have  a  vivid  recollection  of  the  in- 
cessant tossing  of  arms  and  legs  to  keep  our  balance,  and  the 
assistance  we  got  from  a  long  stick  or  a  stone  held  in  our 
hands.  But  the  cyclist  gets  no  help.  His  legs  move  only  in 
the  tread  of  the  wheel,  and  his  hands  rest  quietly  on  the  ends 
of  the  cross-bar  of  his  machine.  The  rope-walker  keeps  every 
muscle  tense,  and  every  limb  in  motion  or  ready  to  move.  No 
wonder,  when  a  tourist  on  his  bicycle  spins  for  the  first  time 
through  a  village  here,  or  among  the  nomads  of  Asia,  he  is  fol- 
lowed by  a  gaping  crowd,  till  his  machine  carries  him  out  of 
their  sight. 

We  involuntarily  ask,  How  is  it  possible  for  one  supported 
on  so  narrow  a  base  to  keep  his  seat  so  securely  and,  seemingly, 
so  without  effort  ? 

For  an  answer  to  this  question  I  have  searched  somewhat 
widely,  and,  while  I  have  found  articles  enough  on  or  about  the 
bicycle,  and  what  has  been  done  by  its  riders,  I  have  found 
none  that  offered  a  reasonable  theory  for  its  explanation.  This 
is  my  apology  for  presenting  the  present  paper.  In  it  I  shall 
state  the  theories  which  have  been  offered,  the  reasons  why 
3  33 


34  ACHIEVEMENTS  IN  SCIENCE 

they  are  unsatisfactory,  and  then  give  what  appears  to  me  the 
true  rationale  of  the  machine. 

The  only  paper  I  found  that  claimed  to  explain  the  bicycle 
was  one  by  Mr.  C.  Vernon  Boys,  entitled  "The  Bicycle  and  its 
Theory."  It  was  delivered  before  a  meeting  of  mechanical 
engineers,  and  is  reported  at  great  length  in  "  Nature,"  vol. 
xxix.  But,  on  examination,  I  found  that,  out  of  several  pages 
of  closely  printed  matter,  the  Theory  occupied  possibly  a  dozen 
lines.  All  the  rest  was  about  the  bicycle  and  what  had  been 
done  on  it,  but  not  another  word  about  its  theory.  We  are 
told  that  Mr.  Boys  exhibited  a  top  in  action,  and  requested  his 
audience  to  notice  its  remarkable  stability.  Then  he  said  that 
the  stability  of  the  bicycle  was  due  to  the  same  principle,  but 
made  no  attempt  to  show  any  connection  between  them.  The 
top  revolves  on  its  axis,  and  it  stays  up  as  you  see ;  the  wheel 
of  the  bicycle  revolves  on  its  axis,  and  therefore  it  stays  up, 
was  his  theory  and  demonstration,  and  the  whole  of  it,  and,  so 
far  as  one  can  judge  from  the  report,  he  was  satisfied,  however 
it  may  have  been  with  his  audience. 

Of  all  machines,  none  seem  to  be  so  little  understood  as  the 
top  and  its  near  relation,  the  gyroscope.  Hence  the  best  that 
can  be  said  is,  that  the  lecturer  availed  himself  of  the  tendency 
found  in  most  minds  to  "  explain  "  an  unfamiliar  phenomenon 
by  referring  it  to  some  other  more  familiar  one,  longer  known, 
but  equally  incomprehensible — as  if,  as  in  grammer,  two  nega- 
tives make  an  affirmative,  so,  in  physics,  two  unknowns  make  a 
known. 

Without  going  into  the  theory  of  the  top,  or  of  the  gyro- 
scope, it  is  easy  to  show  experimentally  that  their  stability  and 
that  of  the  bicycle  must  be  due  to  different  principles.  I  spin 
on  this  table  a  top  with  a  somewhat  blunt  point  (Fig.  i).  You 
notice  it  runs  around  in  a  circular  or  rather  a  spiral  path,  and 
gradually  rises  to  a  perpendicular.  I  strike  it  quite  a  hard 
blow,  but  do  not  upset  it.  I  send  it  flying  across  the  table,  or 
off  to  the  floor,  but  still  it  maintains  its  upright  position.  You 
notice  that,  when  it  is  perpendicular,  it  stands  still ;  but,  if  it 
leans  ever  so  little,  it  immediately  begins  to  swing  or  gyrate 
around  a  vertical  axis.  I  now  change  the  top  for  one  whose 


MODES  OF  TRAVELING  35 

point  is  very  fine  and  well  centered  and  sharp  (Fig.  2).  You 
see  that  it  hardly  travels  at  all.  I  now  cause  the  point  to  fall 
into  a  slight  pit  in  the  surface  of  the  table :  it  ceases  to  travel, 
but  continues  for  a  very  considerable  time  to  swing  around  a 
vertical  axis,  and  is  remarkably  stable,  whatever  the  angle  at 
which  it  leans.  Stopping  its  traveling  has,  as  you  see,  no 
effect  upon  its  stability ;  but  now  I  put  my  pencil  before  the 
axle  and  stop  the  gyration  or  swinging  around.  Immediately 
the  power  of  staying  up  is  gone,  and  the  top  falls.  I  may  vary 
the  experiment  in  every  possible  way :  so  long  as  the  axis  is 
inclined,  the  result  is  the  same;  the  moment  the  gyration 
ceases,  the  top  falls. 

In  the  case  of  the  bicycle  there  is  no  gyrating  around  a 
vertical  axis.     Whatever  else  it  may  do,  it  does  not  do  that. 


Fig.  i. 

Yet,  as  you  saw,  gyration  is  absolutely  essential  to  the  effect 
which  Mr.  Boys  thinks  accounts  for  its  stability. 

We  may,  I  think,  dismiss  the  top  from  further  considera- 
tion ;  but  there  is  another  instrument  apparently  much  closer 
in  its  relation  to  the  bicycle.  I  mean  the  gyroscope,  or  rather 
that  form  of  it  which  Lord  Kelvin  calls  a  gyrostat.  Its  wheel 
is  upright  like  the  bicycle's  (see  Figs.  3  and  4).  The  lower 
part  of  the  ring  which  supports  the  wheel  rests  in  a  kind  of 
trough,  to  the  bottom  of  which  is  attached  crosswise  a  piece  of 
metal  (best  seen  in  Fig.  3)  curved  on  the  lower  edge,  and  with 
two  projecting  wires  by  which  it  may  be  drawn  back  and  forth 
in  the  plane  of  the  wheel. 

I  now  set  the  wheel  in  rapid  motion — much  more  rapid  than 


36  ACHIEVEMENTS  IN  SCIENCE 

any  bicycle-wheel  can  go ;  I  place  it  on  a  smooth,  hard  surface 
—I  have  here  a  pane  of  glass — and  leave  it  to  itself.  It  be- 
gins at  once,  as  you  see,  to  revolve  around  a  vertical  axis.  If 
it  leans  little,  it  revolves  slowly ;  if  it  leans  much,  it  revolves 
faster.  It  will  not  fall  to  the  table,  though  I  push  it,  or  strike 
a  hard  blow.  It  resists  with  remarkable  force.  I  now  take  it 
by  the  projecting  wires  and  attempt  to  make  it  move  in  a 
straight  course,  as  a  bicycle  does  when  it  spins  along  the  road. 
Instantly  it  falls.  The  rotation  of  the  wheel  on  its  axis  was 
not  in  the  slightest  degree  interfered  with,  but  the  stability 
vanishes  the  moment  the  rotation  around  the  vertical  axis 


Fig.  3.  Fig.  4. 

ceases.  Invariably  it  falls.  Yet  you  observe  the  conditions 
are  far  more  favorable  for  the  effect  of  gyrostatic  action  than 
in  the  bicycle,  for  the  mass  of  the  rim  of  our  gyrostat  is  many 
times  heavier  in  proportion  to  its  size,  and  its  speed  incompara- 
bly greater.  I  try  the  experiment  over  and  over,  the  result  is 
always  the  same.  No  amount  of  skillful  management  will 
make  the  instrument  stay  up  for  an  instant  if  it  has  to  move  in 
a  straight  line.  I  submit  that  these  experiments  are  proof 
positive  that  the  sustaining  power  of  the  bicycle  does  not  come 
from  any  gyroscopic  action. 

Others  find  in  its  going  so  fast  the  reason  why  the  bicycle 
does  not  fall — referring,  of  course,  in  a  blind  way  to  that  prin- 
ciple embodied  by  Newton  in  his  first  law:  "A  body  in  motion, 


MODES  OF  TRAVELING  37 

if  left  to  itself,  will  continue  to  move  in  a  straight  line  forever." 
A  brief  examination  will,  I  think,  convince  you  that  this,  too, 
fails  to  account  for  the  effect  which  we  know  is  somehow 
produced. 

It  is  another  principle  in  physics  that  two  forces  acting  at 
right  angles  to  each  other  do  not  interfere.  Each  produces  its 
own  effect  as  fully  as  if  the  other  did  not  act.  Now,  in  case  of 
a  bicyclist,  his  forward  motion,  whether  fast  or  slow,  is  at  right 
angles  to  gravity,  hence  does  not  in  any  way  resist  it;  and, 
therefore,  as  it  is  gravity  that  causes  him  to  tilt  over,  the  for- 
ward motion  will  not  prevent  his  falling. 

But  it  may  be  said  that  the  force  of  gravity  when  the  'cycle 
leans,  say  to  the  right,  is  in  fact  resolved  into  two  components, 
one  vertical  and  the  other  lateral,  and  it  is  the  latter  only  that 
causes  the  bicyclist  to  fall.  This  does  not  help  the  matter,  for 
both  components  are  perpendicular  to  the  course  of  the  bicycle, 
and  hence  its  forward  motion  can  in  no  way  counteract  either 
of  them.  Unless  some  other  force  comes  into  play,  the  bicy- 
clist must  fall  toward  whichever  side  he  happens  to  begin  to  lean. 

Many  think  they  find  this  counteracting  influence  in  "  cen- 
trifugal force."  You  all  are  familiar  with  the  effects  of  this 
"  force."  You  feel  them  every  time  you  turn  a  corner  quickly, 
whether  on  foot  or  in  a  wagon,  or  on  horseback.  The  bare- 
back riders  in  the  circus  lean  well  toward  the  center  of  the 
ring,  to  escape  being  thrown  outward.  We  see  its  effect  when 
the  bicyclist  spins  around  a  corner.  In  such  cases  "  centrifu- 
gal force  "  plays  an  important  part,  and  is  the  real  upholding 
force. 

But  centrifugal  force  is  impossible  so  long  as  the  body 
moves  in  the  same  direction,  i.e.,  in  a  straight  line.  There 
must  be  change  of  direction,  and,  other  things  being  equal,  this 
force  is  greater  in  proportion  to  the  abruptness  of  that  change ; 
or,  as  mathematicians  say,  the  velocity  being  constant,  it  varies 
inversely  as  the  radius  of  the  curve  in  which  the  body  moves. 
The  larger  the  radius,  the  smaller  the  centrifugal  force.  If  the 
radius  of  curvature  becomes  infinite — i.e.,  the  curve  becomes 
a  straight  line — the  centrifugal  force  becomes  infinitely  small 
or  zero. 


38  ACHIEVEMENTS  IN  SCIENCE 

So  long,  therefore,  as  the  bicyclist  does  not  turn  corners — 
keeps  in  a  straight  course — the  centrifugal  force  gives  us  no 
assistance  whatever  in  understanding  why  he  keeps  his  seat  so 
securely.  But  yet  it  may  be  thought  that  this  force,  if  supple- 
mented by  skillful  balancing,  is  sufficient.  It  keeps  the  bicycle 
from  falling  when  turning  corners:  will  not  good  balancing 
account  for  the  stability  when  moving  in  a  straight  course  ? 
We  are  all  familiar  with  the  phenomena  of  balancing  one's  self. 
We  know  the  help  a  heavy  pole  gives  at  such  times ;  how  a 
person's  legs  and  arms  move  with  startling  rapidity  in  the 
opposite  direction  to  that  in  which  he  feels  himself  falling. 
There  is  nothing  of  this  on  the  wheel.  If  the  stability  was  due 
to  balancing,  it  would  not  be  so  very  difficult  for  a  bicyclist  to 
sit  upon  his  machine  when  not  in  motion,  and  when  its  wheels 
both  point  in  the  same  direction.  I  have  never  seen  one  that 
could  do  it.  I  suspect,  however,  that  it  is  not  impossible,  any 
more  than  to  stand  on  the  top  round  of  an  unsupported  ladder. 
But  the  ordinary  bicyclist  cannot  do  it ;  and  yet,  without  appar- 
ent effort,  he  rides  securely.  That  his  stability  is  not  due  to 
his  balancing  and  to  his  rapid  forward  motion  combined,  is  evi- 
dent when  we  reflect  that  if  the  handles  are  made  immovable, 
so  that  neither  of  the  wheels  can  be  turned  to  the  right  or  left, 
it  is  impossible  for  any  ordinary  rider,  no  matter  at  what  speed 
he  may  move,  to  keep  from  falling  for  any  considerable  time 
after  he  once  begins  to  tilt. 

Apparently  the  fact  that  some  can  ride  "  hands  off "  on  a 
safety  wheel  contradicts  this,  for,  however  it  may  be  on  an 
"  ordinary,"  on  a  "  safety "  the  rider  cannot  guide  it  by  the 
pedals,  and  as  he  does  not  touch  the  handles  of  the  steering- 
wheel  or  the  wheel  itself,  it  would  seem  that  his  not  tilting 
must  be  due  to  good  balancing.  Experiment,  however,  proves 
the  contrary.  Let  the  steering  wheel  be  fixed  by  tying  the 
handles,  or  by  a  clamp  on  the  spindle,  so  that  it  cannot  turn  to 
the  right  or  the  left,  and  then  let  the  cyclist  try  to  keep  it 
erect.  Balancing  won't  help,  except  possibly  to  delay  his  fall 
a  few  moments.  And  worse  than  that,  he  can't  ride  hands  off 
at  all  if  he  tries  to  do  so  only  by  balancing.  The  explanation 
of  such  riding  is  not  very  difficult,  but  requires  some  other 


MODES  OF  TRAVELING 


39 


matters  to  be  treated  first.  At  present  all  I  desire  to  establish 
is  that  in  this  kind  of  riding,  as  well  as  in  all  others,  the  rider's 
ability  to  keep  from  falling  to  one  side  for  an  indefinite  time 
while  traveling  in  a  straight  line  is  not  due  to  balancing. 

I  think  you  will  agree  with  me  that  the  reasons  thus  far 
assigned  for  the  stability  of  the  bicycle  cast  little  or  no  light 
upon  the  subject.  Gyration  has  nothing  to  do  with  it  ;  centrif- 


ugal  force  has  no  application  to  it,  except  when  turning  cor- 
ners, or  otherwise  changing  abruptly  the  direction  of  the  move- 
ment ;  balancing  is  a  detriment  rather  than  an  assistance ;  and 
rapid  motion  alone  accounts  for  nothing.  Some  other  explana- 
tion is  needed ;  this  I  shall  now  attempt  to  give. 

Regarded  mathematically  as  a  machine  for  the  application 
of  force,  the  bicycle  is  a  very  simple  affair.  The  weight  (Figs. 
5  and  6)  is  applied  at  the  saddle,  A,  and  is  so  great  that  the 


40  ACHIEVEMENTS  IN  SCIENCE 

center  of  gravity  of  the  whole  is  very  close  to  that  point.  A  B 
and  A  C  are  the  lines  of  force,  B  marking  the  point  where  the 
fore  wheel  rests  on  the  ground,  and  C  where  the  rear  one. 
In  discussing  the  forces  that  act  on  the  machine  we  need  con- 
sider only  these  lines,  all  the  other  parts  being  merely  for  con- 
venience or  ornament.  It  is  evident  that  A  cannot  of  itself  tilt 
either  backward  or  forward,  since  a  vertical  line  from  it  falls 
between  B  and  C.  In  reference  to  them  it  is  in  stable  equi- 


Fig.  6. 

librium,  while  in  regard  to  side  motion  its  equilibrium  is  very 
unstable ;  the  least  thing  will  upset  it. 

To  study  the  matter  more  conveniently,  I  have  had  a  form 
made  which  eliminates  all  unnecessary  parts  and  represents 
only  the  lines  of  force  and  the  weight  on  the  saddle  (Fig.  7). 
It  consists,  as  you  see,  of  two  long,  slender  pieces  of  pine,  and 
looks  like  a  huge  capital  A,  the  cross-piece  serving  merely  to 
hold  the  whole  more  firmly  together.  At  the  apex,  A,  I  have 
placed  a  few  pounds  of  lead  to  represent  the  rider's  weight. 

In  the  older  form  of  the  bicycle,  the  wheel  in  front  is  very 
much  larger.  The  corresponding  leg,  A  B  (Fig.  7),  is  much 
steeper  and  shorter  than  the  other.  In  "  safety  cycles  "  it  is 
just  the  reverse,  the  rear  leg  being  steeper  and  shorter,  while 


MODES  OF  TRAVELING  41 

the  two  wheels  are  of  nearly  the  same  size.  As  the  theory  of 
both  machines  is  the  same,  I  shall,  for  the  present,  speak  only 
of  the  former. 

For  convenience  in  handling,  and  that  it  may  be  better 
seen,  I  place  the  foot  C,  the  rear  one,  on  the  table,  and  hold 
the  other,  B,  in  my  hand,  and  at  the  same  height  from  the 
floor.  Now,  notice :  the  weight  at  the  apex,  or  saddle,  begins 
to  tilt  to  the  right ;  I  quickly  move  my  hand  to  the  right  till  it 
comes  under  the  weight.  If  the  saddle  tilts  to  the  left,  I  move 
my  hand  quickly  to  the  left.  In  every  case,  by  moving  my 
hand  more  rapidly  than  the  weight  tilts,  I  bring  the  point  of 


0  B 

Fig.  7. 

support  under  it.  It  is  very  easy  in  this  way  to  keep  the 
weight  from  falling ;  and  that  is  the  way  the  bicycle  is  kept 
upright. 

But  you  will  ask,  How  can  the  rider  move  the  point  of  sup- 
port when  it  is  on  the  ground,  and  several  feet  out  of  his  reach  ? 
He  does  it  by  turning  the  wheel  to  the  right  or  left,  as  may  be 
necessary — that  is,  by  pulling  the  cross-bar  to  the  right  or  left, 
and  thus  turning  the  forked  spindle  between  whose  arms  the 
steering-wheel  is  held  and  guided. 

But,  some  one  will  say,  How  does  turning  the  wheel  bring 
the  point  of  support  to  the  right  or  left — whichever  the  machine 
may  happen  to  be  leaning  ? 

Let  us  suppose  a  'cyclist  mounted  on  his  wheel  and  riding, 
say,  toward  the  north.  He  finds  himself  beginning  to  tilt 


42  ACHIEVEMENTS  IN  SCIENCE 

toward  his  right.  He  is  now  going  not  only  north  with  the 
machine,  but  east  also.  He  turns  the  wheel  eastward.  The 
point  of  support,  B  (Fig.  5),  must  of  necessity  travel  in  the 
plane  of  the  wheel,  hence  it  at  once  begins  to  go  eastward,  and, 
as  it  moves  much  faster  than  the  rider  tilts,  it  quickly  gets 
under  him,  and  the  machine  is  again  upright.  To  one  stand- 
ing at  a  distance,  in  front  or  rear,  the  bottom  of  the  wheel  will 
be  seen  to  move  to  the  right  and  left,  just  as  I  moved  the  foot 
of  the  skeleton  frame  a  moment  ago. 

I  conclude,  then,  that  the  stability  of  the  bicycle  is  due  to 
turning  the  wheel  to  the  right  or  left,  whichever  way  the  lean- 
ing is,  and  thus  keeping  the  point  of  support  under  the  rider, 
just  as  a  boy  keeps  upright  on  his  finger  a  broomstick  standing 
on  its  smallest  end. 

It  may  be  questioned  whether  the  bottom  point  of  the 
wheel  really  travels  faster  than  the  weight  at  the  saddle  tilts 
over,  and,  if  it  does  not,  then  the  explanation  which  I  have 
been  giving  fails. 

By  an  easy  calculation,  based  on  the  well-known  principle 
that  the  velocity  of  a  body  moving  under  the  influence  of  gravi- 
tation varies  as  the  square  root  of  the  height  from  which  it  has 
fallen,  irrespective  of  the  character  of  the  path  it  has  described, 
I  find  that  when  the  rider's  seat  is,  e.g.,  sixty  inches  high,  and 
the  machine  has  inclined,  say,  six  inches  out  of  the  perpendicu- 
lar, it  is  at  that  instant,  if  free  to  fall,  tilting  over  at  the  rate  of 
much  less  than  a  mile  an  hour.  But  six  inches  is  a  large 
amount  to  lean — a  good  cyclist  does  not  lean  that  much — we 
will  suppose  him  out  of  plumb  only  three  inches;  then  his 
lateral  movement  will  be  at  the  rate  of  only  some  twenty-two 
hundred  feet  in  an  hour.  If  the  tilt  is  less,  the  falling  rate  will 
be  less.  To  keep  the  center  of  gravity  over  the  base,  the  bot- 
tom of  the  wheel  needs  only  to  move  to  the  right  or  left,  which- 
ever the  machine  is  leaning — somewhat  faster  than  these  slow 
rates.  There  is  no  great  difficulty  in  doing  this,  for,  if  the  bi- 
cycle is  going  eight  miles  an  hour,  it  is  necessary  to  change  its 
course  only  about  seven  degrees ;  if  four  miles,  then  only  about 
fourteen  degrees;  if  two  miles,  then  about  twenty-eight  de- 
grees. The  greater  the  speed,  the  less  the  angle:  at  sixteen 


MODES  OF  TRAVELING  43 

miles  an  hour,  the  wheel  would  need  to  be  turned  less  than  two 
degrees.  From  which  follows  the  fact,  well  known  to  cyclists, 
that  the  slower  the  machine  is  traveling  the  more  the  handles 
must  be  turned,  and  the  more  difficult  to  keep  from  falling. 

From  the  fact  that  the  bicycle  is  kept  erect  by  keeping  its 
point  of  support  under  it,  like  a  pole  standing  upright  on  one's 
finger,  some  curious  and,  to  most  persons,  quite  surprising  re- 
sults follow.  I  have  here  three  rods,,  respectively  one  foot, 
three  feet,  and  seven  feet  long.  I  hold  the  last,  as  you  see, 
very  easily ;  the  second  not  so  easily ;  and  the  first  only  with 
considerable  difficulty.  I  now  put  a  cap  of  lead  weighing  four 
or  five  pounds  on  the  top  of  each,  and  then  again  support  them 
as  before.  In  every  case  it  is  now  easier  to  keep  them  from 
falling.  Hence,  in  a  bicycle,  the  higher  and  the  heavier  the 
load,  the  less  the  danger  of  falling ;  and,  as  most  of  the  weight 
is  in  the  saddle,  the  center  of  gravity  of  the  whole  is  very  near 
it,  and  it  is  the  height  of  that,  and  not  the  size  of  the  wheel, 
that  affects  the  lateral  stability.  A  rider  with  a  load  on  his 
back,  whether  a  bag  of  grain  or  a  man  sitting  on  his  shoulders, 
is  by  all  that  the  more  safe  from  falling  either  to  the  right  or 
left,  however  it  may  be  as  to  headers. 

Experts  sometimes  ride  for  a  considerable  distance  with 
both  legs  over  the  cross-bar.  But  there  is  nothing  strange  in 
this,  for  placing  their  legs  in  that  position  only  raises  the  center 
of  gravity,  and  hence  really  adds  to  the  stability.  If  in  some 
way  they  can  manage  to  turn  the  cross-bar,  they  can  ride  with- 
out difficulty  until  the  momentum  is  exhausted. 

A  much  more  difficult  feat  is  to  ride  on  one  wheel.  The 
small  wheel — the  rider  holding  the  other  in  the  air — is  most  eas- 
ily managed.  It  is  merely  a  case  of  supporting  on  a  small  base 
a  long,  upright  body.  One  keeps  moving  the  point  of  support 
so  as  to  bring  it  under  the  center  of  gravity.  It  needs  only  a 
quick  eye  and  a  steady  hand.  It  is  much  more  difficult  when 
the  cyclist  uses  only  the  big  wheel,  the  other  having  been  re- 
moved, for  he  is  liable  to  fall  forward  or  backward,  as  well  as 
to  either  side.  To  avoid  the  first  and  second,  he  leans  forward 
a  little  beyond  his  base,  and  would  pitch  headlong,  but  that  he 
drives  the  wheel  forward  by  means  of  the  treadles  just  fast 


44  ACHIEVEMENTS  IN  SCIENCE 

enough  to  prevent  it.  We  all  do  the  same  thing  when  we 
walk.  We  lean  so  far  forward  that  we  would  fall,  did  we  not 
keep  moving  our  feet  fast  enough  to  prevent  it.  On  the  single 
wheel  most  of  us  would  fail,  because  from  lack  of  experience 
we  would  make  the  wheel  go  too  fast,  and  so  would  fall  back- 
ward; or  else,  not  fast  enough  to  keep  from  falling  on  our 
faces.  As  to  falling  sidewise,  that  is  prevented  exactly  as 
when  both  wheels  are  used — the  rider  turns  the  crossbar  to  the 
right  or  left,  and  propels  the  machine  in  that  direction.  Expe- 
rience, a  level  head,  and  a  steady  hand  tell  how  far  to  turn  it. 

From  mere  inspection  of  Figure  5  we  see  that  safety  against 
headers  varies  inversely  as  the  height  of  the  saddle,  and  directly 
as  the  distance  from  the  foot  of  the  perpendicular  A  D  to  the 
forward  point  of  support  B  (Figs.  5  and  6).  In  other  words, 
the  higher  the  saddle,  the  greater  the  danger  of  headers ;  and 
the  farther  back,  the  less  the  danger. 

As  to  the  law  of  lateral  safety — i.e.,  against  falling  sidewise 
— it  is  in  one  respect  the  reverse  of  the  other,  for  the  greater 
the  height  of  the  saddle,  the  easier  not  to  fall  to  either  side, 
just  as  it  is  easier  to  keep  upright  on  the  end  of  my  finger  a 
long  stick  than  a  short  one. 


CONVEYANCE  OF  THOUGHT 


From   Mail   Coach   to   Telephone 

By  ALFRED  RUSSEL  WALLACE 

THE  history  of  the  progress  of  communication  between  per- 
sons at  a  distance  from  each  other  has  gone  through 
three  stages  which  are  radically  distinct.  At  first  it  was  de- 
pendent on  the  voice  or  on  gestures,  and  a  message  to  a  friend 
(or  enemy)  at  a  distance  could  be  sent  only  through  a  messen- 
ger, and  was  liable  to  distortion  through  failure  of  memory. 
The  heralds  and  ambassadors  of  early  times  thus  communicated 
orders  from  kings  to  their  subjects,  or  conveyed  messages  from 
one  king  to  another.  Then  came  the  invention  of  writing,  and 
a  new  era  of  communication  began.  Letters  were  capable  of 
conveying  secret  information  and  copious  details,  which  could 
not  be  safely  intrusted  to  the  uncertain  memory  of  an  interme- 
diary ;  and  a  single  messenger  could  convey  a  large  number  of 
letters  to  various  persons  on  the  way  to  his  ultimate  destina- 
tion. Henceforth  the  progress  of  communications  was  bound 
up  with  that  of  locomotion,  and,  as  civilization  advanced, 
arrangements  were  made  for  the  conveyance  of  letters  at  a 
comparatively  small  cost.  A  post-office  for  the  public  service 
was  first  established  by  some  Continental  merchants  in  the 
fourteenth  century;  but  it  was  not  till  the  time  of  Charles  I. 
that  anything  of  the  kind  was  to  be  found  in  England,  and  then 
it  was  mainly  for  the  purpose  of  keeping  up  a  communication 
between  London  and  Edinburgh,  and  the  intervening  large 
towns,  for  Government  purposes.  It  was,  however,  the  start- 
ing-point of  our  existing  postal  system,  which  has  been  gradu- 
ally extended  under  the  direction  of  the  King's  postmaster- 

45 


46  ACHIEVEMENTS  IN  SCIENCE 

general,  and  has  continued  to  be  a  government  monopoly  to 
our  day.  The  letters  were  carried  on  horseback  till  1783,  when 
mail  coaches  were  first  introduced ;  and  these  led  to  a  great  im- 
provement in  our  main  roads,  and  the  extension  of  the  postal 
service  to  every  town  and  village  in  the  kingdom. 

But  even  with  good  roads  and  mail  coaches,  the  actual  time 
taken  in  the  dispatch  of  a  letter  to  a  distant  place  was  little  if 
any  less  than  had  been  possible  from  the  earliest  times,  by 
means  of  relays  of  runners  on  foot  or  by  swift  horsemen.  The 
improvement  consisted  in  the  regularity  and  economy  of  the 
postal  service.  The  introduction  of  railways  and  steamships 
enabled  much  greater  speed  to  be  secured;  but  the  greatest 
and  most  beneficial  improvement  in  the  administration  of  the 
post-office  was  that  inaugurated  by  Rowland  Hill  in  1840.  The 
rule  then  first  introduced,  of  a  uniform  charge  irrespective  of 
distance,  is  one  of  those  entirely  new  departures  so  many  of 
which  characterize  our  century,  and  which  not  only  produce 
immediate  beneficial  effects,  but  are  the  starting-points  of  vari- 
ous unforeseen  developments.  It  was  founded  in  this  case  on 
a  careful  estimate  of  the  various  items  which  make  up  the  cost 
of  the  carriage  and  delivery  of  each  letter,  and  it  was  shown 
that  the  actual  conveyance,  even  for  the  greatest  distances, 
was  the  smallest  part  of  the  cost  when  the  number  of  letters  is 
large,  the  chief  items  of  expense  being  the  office  work — the 
sorting,  stamping,  packing,  etc. — and  the  final  delivery,  all  of 
which  are  quite  independent  of  the  distance  the  letter  is  car- 
ried. The  old  system,  therefore,  of  increasing  the  charge  for 
postage  in  proportion  to  distance  was  altogether  unreasonable, 
because  the  cost  of  conveyance  was  hardly  perceptibly  in- 
creased ;  and  if  the  post-office  was  considered  to  be  a  public 
service  for  the  public  benefit  only,  the  people  had  a  right  to 
demand  that  they  should  pay  only  in  proportion  to  the  cost. 
Yet  the  principle  was  not  at  first,  and  is  not  even  now,  fully 
carried  out.  For  thirty  years,  from  1840  to  1871,  the  postage 
was  increased  equally  with  each  successive  increment  of  weight, 
the  half-ounce  letter  being  a  penny,  while  one  of  two  ounces 
was  four-pence.  But  as  the  chief  items  of  expense— the  office 
work  and  delivery— were  the  same,  or  nearly  the  same,  in  both 


CONVEYANCE  OF  THOUGHT  47 

cases,  the  double  or  quadruple  charge  was  entirely  opposed  to 
the  principle  on  which  the  uniform  rate  was  originally  founded. 
Accordingly,  in  1871,  when  an  ounce  letter  was  first  carried 
for  a  penny,  the  charge  for  two  ounces  was  fixed  at  three  half- 
pence, while  four  ounces  was  taken  for  twopence.  This 
accepted  and  common-sense  principle,  however,  has  not  yet 
been  applied  to  the  charges  of  the  Postal  Union,  so  that  a  letter 
which  is  a  fraction  over  the  half -ounce  is  charged  fivepence,  or 
double,  and  one  over  an  ounce  and  a  half  tenpence,  or  four 
times  that  of  the  half -ounce  letter,  although  an  extra  halfpenny 
would  t  probably  cover  the  extra  cost  of  the  service  in  both 
cases. 

The  same  inability  of  the  official  mind  to  carry  out  an  ad- 
mitted principle  is  seen  also  in  the  case  of  Postal  Orders. 
The  cost  to  the  post-office  of  receiving  and  paying  money  is  ex- 
actly the  same  whether  the  amount  is  eighteenpence  or  fifteen 
shillings,  and  there  is  neither  justice  nor  common  sense  in 
charging  three  times  as  much  in  the  latter  case.  There  is  no 
risk,  because  the  money  is  paid  in  advance ;  and  as  the  amounts 
taken  in  and  paid  out  for  postal  orders  must  be  approximately 
equal,  it  is  difficult  to  see  what  justification  there  is  for  making 
any  difference  in  charge.  The  same  objection  applies  to  money 
orders;  and  as  there  is  doubtless  a  certain  percentage  of  both 
which,  from  various  causes,  are  never  presented  for  payment, 
the  profit  to  the  post-office  must  be  greater  in  case  of  the 
higher  amounts,  which  is  another  reason  why  these  should  not 
be  exceptionally  taxed.  When  the  railways  are  taken  over  by 
the  state,  to  be  worked  for  the  good  of  the  community  only, 
the  principle  will  admit  of  great  extension,  each  increment  of 
distance  being  charged  at  a  lower  rate,  just  as  is  each  incre- 
ment of  weight  in  our  inland  letters. 

The  third  stage  in  the  means  of  communication,  when  by 
means  of  electric  signals  it  was  rendered  independent  of  loco- 
motion, is  that  which  has  especially  distinguished  the  present 
century.  The  electric  telegraph  serves  us  as  a  new  sense,  ena- 
bling us  to  communicate  with  friends  at  the  other  side  of  the 
globe  almost  as  rapidly  and  as  easily  as  if  they  were  in  different 
parts  of  the  same  town.  The  means  of  communication  we  now 


48  ACHIEVEMENTS  IN  SCIENCE 

use  daily  would  have  been  wholly  inconceivable  to  our  ances- 
tors a  hundred  years  ago. 

About  the  middle  of  the  last  century  it  was  perceived  by  a 
few  students  of  electricity  that  it  afforded  a  means  of  commu- 
nication at  a  distance;  but  it  was  not  till  the  year  1837  that  the 
efforts  of  many  simultaneous  workers  overcame  the  numerous 
practical  difficulties,  and  the  first  electric  telegraph  was  estab- 
lished. Its  utility  was  so  great,  especially  in  the  working  of 
the  railways  then  being  rapidly  extended  over  the  kingdom, 
that  it  soon  came  into  general  use ;  but  hardly  any  one  at  first 
thought  that  it  would  ever  be  possible  to  lay  wires  across  the 
ocean  depths  to  distant  continents.  Yet,  step  by  step,  with 
wonderful  rapidity,  even  this  was  accomplished.  The  first 
submarine  line  was  laid  from  Dover  to  Calais  in  1851;  and 
only  five  years  afterward,  in  1856,  a  company  was  formed  to 
lay  an  electric  cable  across  the  Atlantic.  The  cable,  2,500 
miles  long  and  weighing  a  ton  per  mile,  was  successfully  laid, 
in  1858,  from  Ireland  to  Newfoundland;  but  owing  to  the 
weakness  of  the  electric  current,  and  perhaps  to  imperfections 
in  the  cable,  it  soon  became  useless,  and  had  to  be  abandoned. 
After  eight  years  more  of  invention  and  experiment,  another 
cable  was  successfully  laid  in  1866;  and  there  are  now  no  less 
than  fourteen  lines  across  the  Atlantic,  while  all  the  other 
oceans  have  been  electrically  bridged,  so  that  messages  can  be 
sent  to  almost  any  part  of  the  globe  at  a  speed  which  far  sur- 
passes the  imaginary  power  of  Shakespeare's  sprite  Ariel, 
who  boasted  that  he  could  "  put  a  girdle  round  about  the  earth 
in  forty  minutes."  We  are  now  able  to  receive  accounts  of 
great  events  almost  while  they  are  happening  on  the  other  side 
of  the  globe;  and,  owing  to  difference  of  longitude,  we  some- 
times can  hear  of  an  event  apparently  before  it  has  happened. 
If  some  great  official  were  to  die  at  Calcutta  at  sunset,  we 
should  receive  the  news  in  London  soon  after  noon  on  the  same 
day. 

As  a  result  of  the  numerous  experimental  researches  neces- 
sitated for  the  continuous  improvement  of  the  electric  tele- 
graph, the  telephone  was  invented,  an  even  more  marvelous 
and  unexpected  discovery.  By  it,  the  human  voice,  in  all  its 


CONVEYANCE  OF  THOUGHT  49 

countless  modifications  of  equality  and  musical  tone,  and  its 
most  complex  modulations  during  speech,  is  so  reproduced  at 
a  distance  that  a  speaker  or  singer  can  be  distinctly  heard  and 
understood  hundreds  of  miles  away.  This  is  not  an  actual 
transmission  of  the  voice,  as  in  the  case  of  a  speaking-tube,  but 
a  true  reproduction  by  means  of  two  vibrating  disks :  the  one 
set  in  motion  by  the  speaker,  while  the  electric  current  causes 
identical  vibrations  in  the  similar  disk  at  the  end  of  the  line, 
and  these  vibrations  reproduce  the  exact  tones  of  the  voice  so 
as  to  be  perfectly  intelligible.  At  first  telephones  could  only 
be  worked  successfully  for  short  distances,  but  by  continuous 
improvements  the  distance  has  been  steadily  increased,  so 
that  in  America  there  is  a  telephone  line  now  in  operation  be- 
tween New  York  and  Chicago,  cities  about  a  thousand  miles 
apart. 

Those  who  have  read  Mr.  Bellamy's  story,  "  Looking  Back- 
ward," will  remember  the  concerts  continually  going  on  day 
and  night,  with  telephonic  connections  to  every  house,  so  that 
every  one  could  listen  to  the  very  best  obtainable  music  at  will. 
But  few  persons  are  aware  that  a  somewhat  similar  use  of  the 
telephone  is  actually  in  operation  at  Buda-Pesth  in  the  form  of 
a  telephonic  newspaper.  At  certain  fixed  hours  throughout 
the  day  a  good  reader  is  employed  to  send  definite  classes  of 
news  along  the  wires  which  are  laid  to  subscribers'  houses  and 
offices,  so  that  each  person  is  able  to  hear  the  particular  items 
he  desires,  without  the  delay  of  its  being  printed  and  circu- 
lated in  successive  editions  of  a  newspaper.  It  is  stated  that 
the  news  is  supplied  to  subscribers  in  this  way  at  little  more 
than  the  cost  of  a  daily  newspaper,  and  that  it  is  a  complete 
success. 

We  thus  see  that  during  the  present  century  two  distinct 
modes  of  communication  with  persons  at  a  distance  have  been 
discovered  and  brought  into  practical  use,  both  of  which  are 
perfectly  new  departures  from  the  methods  which,  with  but 
slight  modifications,  had  been  in  use  since  that  early  period 
when  picture  writing  or  hieroglyphics  were  first  invented. 

In  the  facilities  and  possibilities  of  communication  with  our 
fellow-men  all  over  the  world,  the  advance  made  in  the  present 


50  ACHIEVEMENTS  IN  SCIENCE 

century  is  not  only  immensely  greater  than  that  effected  during 
the  whole  preceding  period  of  human  history,  but  is  even  more 
marvelous  in  its  results.  And  it  is  also  much  greater  in 
amount  than  the  almost  simultaneous  advance  in  facilities  for 
locomotion,  great  as  these  have  been. 


CONVEYANCE  OF  THOUGHT 


Wireless  Telegraphy 

By  RAY  STANNARD  BAKER 

MARCONI  was  a  mere  boy  when  he  first  began  to  dream 
of  the  marvelous  possibility  of  sending  telegraph  mes- 
sages without  wires.  He  was  barely  twenty-one,  a  shy,  modest 
youth,  when  he  went  up  to  London  from  his  quiet  country 
home  in  Italy  to  tell  the  world  about  one  of  the  greatest  inven- 
tions of  the  century.  A  few  months  later  this  boy  had  set  up 
his  apparatus  and  was  telegraphing  all  sorts  of  messages  through 
the  air,  through  walls,  through  houses  and  towns,  through 
mountains,  and  even  through  the  earth  itself,  and  that  with  a 
mechanism  hardly  more  complicated  or  expensive  than  a  toy 
telephone.  The  present  system  of  telegraphy  by  means  of 
wires,  the  sending  of  long  dispatches  over  continents  and  under 
oceans,  is  quite  wonderful  enough  in  itself,  but  here  was  an  in- 
ventor who  did  away  entirely  with  wires  and  all  other  means 
of  mechanical  connection,  and  sent  his  messages  directly 
through  space.  It  is  for  this  that  Marconi  was  famous  the 
world  over  at  twenty-five. 

The  young  inventor  is  tall  and  slender,  and  dark  of  com- 
plexion. Although  he  bears  an  Italian  name  and  was  born  in 
Bologna,  Italy  (in  1874),  and  educated  at  Bologna,  Leghorn, 
and  Florence,  he  is  only  half  Italian,  his  mother  being  an  Eng- 
lishwoman. He  speaks  English  readily  and  fluently,  and  he 
appears  to  like  London  better  than  his  native  land.  His  first 
experiments  were  carried  on  in  the  fields  of  his  father's  estate, 
and  consisted  merely  of  tin  boxes  set  up  on  poles  of  varying 
heights,  one  of  which  was  connected  with  a  crude  transmitting 

51 


52  ACHIEVEMENTS  IN  SCIENCE 

machine,  and  the  other  with  an  equally  crude  receiver,  which 
he  himself  had  manufactured. 

Before  going  into  the  details  of  Guglielmo,  or  William, 
Marconi's  apparatus  and  telling  more  of  his  astonishing  suc- 
cesses, it  may  be  well  to  look  somewhat  into  the  theories  on 
which  he  bases  his  work.  It  must  be  understood,  however, 
that  Marconi  was  not  the  first  to  suggest  wireless  telegraphy, 
nor  to  signal  experimentally  for  short  distances  without  wires ; 
but  he  was  the  first  to  perfect  a  system  and  to  put  it  into  prac- 
tical operation,  and  to  him,  therefore,  belong  the  laurels  of  the 
invention.  Our  own  Prof.  S.  F.  B.  Morse,  the  inventor  of 
telegraphy,  experimented  with  wireless  signals,  and  so  did  Dr. 
Oliver  Lodge  and  W.  H.  Preece  of  London,  Thomas  A.  Edison, 
Nikola  Tesla,  Professor  Trowbridge  of  Harvard,  and  others. 

In  sending  messages  through  space,  Marconi  deals  with 
that  mysterious  all-pervading  substance  known  as  the  ether. 
In  the  English  language  the  word  "  ether  "  has  two  totally  dif- 
ferent meanings.  It  is  the  name  of  a  clear,  colorless  liquid, 
which  is  used  in  surgical  operations  for  easing  a  patient  of  pain. 
Every  one  has  heard  of  "  taking  ether."  This  liquid,  however, 
has  nothing  to  do  with  the  present  subject,  and  it  should  be 
entirely  dismissed  from  the  mind.  The  ether  which  carries 
Marconi's  messages  is  a  colorless,  odorless,  unseen,  inconceiva- 
bly rarefied  substance  which  is  supposed  to  fill  all  space.  Sci- 
entists know  almost  nothing  as  to  its  properties,  but  they  do 
know  that  it  will  vibrate,  and  they  have  called  these  vibrations 
electricity,  heat,  and  light. 

It  seems  strange  enough  that  we  should  use  the  ether  every 
time  we  build  a  fire  under  the  tea-kettle,  every  time  we  read 
by  the  light  of  a  gas-jet,  every  time  we  talk  over  the  telephone, 
and  yet  know  next  to  nothing  about  it. 

Throw  a  stone  into  a  pond  and  you  will  produce  a  series  of 
small  waves  or  ripples — in  other  words,  water  vibrations. 
Strike  a  bell,  and  vibrations  in  the  air  bring  the  sound  to  your 
ear.  In  a  similar  way  ether  has  its  own  peculiar  vibrations. 
For  instance,  a  star  millions  of  miles  away  starts  the  enor- 
mously rapid  vibrations  of  light,  and  these  vibrations  finally 
reach  our  eyes,  as  the  ripples  in  a  pond  reach  the  shore.  We 


CONVEYANCE  OF  THOUGHT  53 

do  not  really  see  the  star ;  we  are  merely  conscious  of  light 
waves  in  the  ether.  In  the  same  manner  ethereal  vibrations 
bring  us  the  heat  and  light  of  the  sun,  and  the  awful  energy  of 
the  lightning  stroke.  From  this  we  know  that  the  ether  ex- 
tends everywhere  through  space,  and  that  the  sun  and  the  earth 
and  the  stars  are  set  in  it,  like  cherries  in  a  jelly.  Light  will 
pass  through  such  a  hard,  brittle  substance  as  glass,  heat  will 
go  through  iron,  and  electricity  "flows"  in  a  copper  wire. 
These  facts  show  us  that  the  ether  must  be  inside  of  the  glass 
and  the  iron  and  the  copper,  else  the  vibrations  would  not  go 
through.  In  the  same  way  the  air  is  full  of  ether,  and  so  are 
our  bodies  and  everything  else,  for  science  knows  nothing 
which  entirely  resists  the  passage  of  heat,  light,  and  electricity. 
We  call  some  substances  solids,  owing  to  their  hardness,  but 
so  far  as  the  ether  is  concerned  there  is  no  such  thing  as  a 
solid.  Every  atom,  even  of  the  hardest  diamond,  is  afloat  in 
ether. 

But  if  heat,  light,  and  electricity  are  all  caused  by  ether 
waves,  how  can  we  tell  them  apart  ? 

The  larger  the  stone  you  throw  into  the  pond  the  larger 
the  waves  produced  and  the  more  rapidly  they  travel.  In  a 
similar  way,  ether  waves  are  of  widely  different  lengths  and 
rapidity  or  frequency.  Vibrations  of  one  speed  give  light, 
another  speed  give  heat,  and  still  another  give  electricity.  Sci- 
ence has  learned  by  a  series  of  wonderful  experiments  that  if 
the  ether  vibrates  at  the  inconceivable  swiftness  of  four  hun- 
dred trillions  of  waves  every  second,  we  see  the  color  red,  if 
twice  as  fast  we  see  violet.  If  more  slowly,  from  two  hundred 
to  four  hundred  trillions  to  the  second,  we  experience  the  sen- 
sation of  heat.  If  more  rapidly  than  violet,  we  have  what 
science  knows  as  "  unseen  light " — the  actinic  rays  and,  prob- 
ably, X-rays.  Our  eyes  will  take  in  only  seven  colors  with 
vibrations  from  four  hundred  to  eight  hundred  trillions  a  sec- 
ond. If  our  eyes  were  better  we  might  see  other  degrees  of 
vibrations,  such  as  X-rays  and  various  electrical  currents,  and 
know  new  colors,  stranger  and  more  beautiful,  perhaps,  than 
any  that  we  now  see. 

Ether  waves  should  not  be  confused  with  air  waves.     Sound 


54  ACHIEVEMENTS  IN  SCIENCE 

is  a  result  of  the  vibration  of  the  air ;  if  we  had  ether  and  no 
air  we  should  still  see  and  feel  heat  and  electricity,  but  there 
would  be  nothing  to  hear.  Air  or  sound  waves  are  very  slow 
compared  with  ether  waves.  A  man's  ordinary  voice  produces 
only  about  one  hundred  and  thirty  waves  a  second,  a  woman's 
shrill  scream  will  reach  2,000  vibrations — a  mere  nothing  com- 
pared with  the  hundreds  of  trillions  which  represent  light. 
Nor  do  air  waves  travel  as  rapidly  as  ether  waves.  In  a  storm 
the  ether  brings  the  flash  of  the  lightning  long  before  the  air 
brings  the  sound  of  thunder,  as  every  one  knows. 

Now,  to  get  down  to  electricity.  Certain  vibrations  of  the 
ether  are  recognized  as  electricity — and  there  are  many  kinds 
of  electrical  waves  to  correspond  with  different  degrees  of 
vibration.  Inventors  have  been  able  to  utilize  electricity  by 
producing  these  ether  waves  by  artificial  means.  I  have  com- 
pared the  ether  to  a  jelly.  The  electrician  merely  jars  this 
jelly,  and  the  vibrations  which  we  know  as  a  "  current "  are 
produced.  A  current  does  not  really  pass  through  a  telegraph 
wire — it  does  not  flow  like  water  in  a  pipe — although  our  com- 
mon language  has  no  other  means  of  expressing  its  passage. 
In  reality  a  vibration  is  started  at  one  end  of  the  wires,  and 
it  is  the  wave  that  travels.  Set  up  a  row  of  toy  blocks.  Tip 
over  the  first  one,  and  it  will  tip  over  the  second,  and  so  on  to 
the  end.  The  blocks  stay  where  they  are,  but  the  motion  or 
wave  goes  onward  to  the  end.  An  electric  wave  is,  of  course, 
invisible.  Imagine  a  cork  on  the  surface  of  a  pond  at  any  dis- 
tance from  the  place  where  a  stone  is  dropped ;  the  cork,  when 
the  wave  reaches  it,  will  bob  up  and  down.  Now,  though  we 
cannot  see  the  electric  wave,  we  can  devise  an  arrangement 
which  indicates  the  presence  of  the  wave  exactly  after  the 
manner  of  a  cork. 

Electric  waves  were  discovered  in  1842  by  Joseph  Henry, 
an  American.  He  did  not  use  the  phrase  "  electric  waves  " ; 
but  he  discovered  that  when  he  produced  an  electric  spark  an 
inch  long  in  a  room  at  the  top  of  his  house,  electrical  action 
was  instantly  set  up  in  another  wire  circuit  in  his  cellar.  There 
was  no  visible  means  of  communication  between  the  two  circuits, 
and  after  studying  the  matter  he  saw  and  announced  that  the 


CONVEYANCE  OF  THOUGHT  55 

electric  spark  set  up  some  kind  of  an  action  in  the  ether,  which 
passed  through  two  floors  and  ceilings  each  fourteen  inches 
thick,  and  caused  "  induction  " — set  up  what  is  called  an  induced 
current — in  the  wires  in  the  cellar.  This  fact  of  induction  is 
now  one  of  the  simplest  and  most  commonplace  phenomena  in 
the  work  of  electricians.  Edison  has  already  used  it  in  tele- 
graphing from  a  flying  train.  Hertz,  the  great  German  inves- 
tigator, developed  the  study  of  these  waves,  and  announced 
that  they  penetrated  wood  and  brick,  but  not  metal.  The 
"  Hertzian  wave  "  is,  indeed,  an  important  feature  of  wireless 
telegraphy.  Strange  to  say,  however,  considering  the  number 
of  brilliant  electricians  in  the  world,  and  the  great  interest  in 
electrical  phenomena,  it  was  left  to  the  young  Italian,  Marconi, 
to  frame  the  largest  conception  of  what  might  be  done  with 
electric  waves,  and  to  invent  instruments  for  doing  it. 

Marconi's  reasoning  was  exceedingly  simple.  The  ether  is 
everywhere ;  it  is  in  the  air  and  in  the  mountains  and  in  houses 
as  well  as  in  a  copper  wire.  Electricity  must,  therefore,  pass 
through  the  air  and  the  mountain  as  well  as  through  the  wire. 
The  difficulty  lay  in  making  an  apparatus  that  would  produce  a 
peculiar  kind  of  wave,  and  to  catch  or  receive  this  wave  in  a 
second  apparatus  located  at  a  distance  from  the  first.  This  he 
finally  succeeded  in  doing  by  the  use  of  waves  similar  to  those 
produced  by  Hertz,  which  he  excited  in  a  specially  constructed 
apparatus.  These  waves  have  a  frequency  of  about  two  hun- 
dred and  fifty  millions  every  second.  From  the  generating 
apparatus  this  peculiar  current  is  communicated  to  a  wire  which 
hangs  from  the  top  of  a  long  pole  or  mast,  or  from  a  kite,  and 
it  passes  by  induction,  through  miles  of  air  and  earth  and  build- 
ings, to  a  second  hanging  wire,  which  conveys  it  to  a  receiving 
instrument,  where  the  signals  are  registered.  To  understand 
this  transfer  we  must  understand  exactly  what  induction  means. 
An  electrical  current  may  be  conducted  through  copper  wire, 
water,  iron,  or  any  other  good  "  conductor."  In  induction  the 
current  passes  directly  through  the  ether.  When  a  current  of 
electricity  passes  through  a  wire,  magnetism  is  present  around 
that  wire ;  and  if  another  wire  be  brought  within  the  magnetic 
field  of  the  charged  wire  and  placed  parallel  with  it,  it  will  also 


56  ACHIEVEMENTS  IN  SCIENCE 

become  charged  with  electricity.  That  is  induction,  and  it  ena- 
bles Marconi  to  send  his  messages  across  the  Channel  from 
England  to  France,  from  ships  on  the  sea  to  shore,  from  light- 
house to  lighthouse,  and  across  wide  stretches  of  open  country. 

And  now,  having  come  to  an  understanding  of  the  theory 
of  sending  messages  without  wires,  we  may  take  a  look  at 
Marconi's  actual  apparatus  as  it  is  now  transmitting  messages 
from  the  Needles  in  Alum  Bay,  at  the  extreme  west  end  of  the 
Isle  of  Wight,  eighteen  miles  across  the  Channel,  to  Poole  on 
the  mainland  of  England. 

From  the  very  peak  of  Marconi's  telegraph  mast  at  the 
Needles  hangs  a  line  of  wire  that  runs  through  a  window  into 
the  little  sending  room.  Here  two  matter-of-fact  young  men 
are  at  work  as  calmly  as  any  ordinary  telegraphers,  talking 
through  the  ether.  One  of  them  has  his  fingers  on  a  black- 
handled  key.  He  is  saying  something  to  the  Poole  station 
eighteen  miles  away  in  England. 

"  Brripp — brripp — brripp — brrrrrr. 
Brripp — brripp — brripp — brrrrrr — 
Brripp — brrrrrr — brripp.     Brripp — brripp ! " 

So  speaks  the  sender  with  noise  and  deliberation.  It  is  the 
Morse  code  working — ordinary  dots  and  dashes  which  can  be 
made  into  letters  and  words,  as  everybody  knows.  With  each 
movement  of  the  key,  bluish  sparks  jump  an  inch  between  the 
two  brass  knobs  of  the  induction  coil,  the  same  kind  of  coil  and 
the  same  kind  of  sparks  that  are  familiar  in  experiments  with 
the  Rontgen  rays.  For  one  dot,  a  single  spark  jumps;  for  one 
dash,  there  comes  a  stream  of  sparks.  One  knob  of  the  induc- 
tion coil  is  connected  with  the  earth,  the  other  with  the  wire 
hanging  from  the  masthead.  Each  spark  indicates  a  certain 
impulse  from  the  electrical  battery ;  each  one  of  these  impulses 
shoots  through  the  wire,  and  from  the  wire  through  space  by 
vibrations  of  the  ether,  traveling  at  the  speed  of  light,  or  seven 
times  around  the  earth  in  a  second.  That  is  all  there  is  in  the 
sending  of  these  Marconi  messages.  Any  person  of  fair  intel- 
ligence could  learn  to  do  it,  Morse  code  and  all,  in  a  few  hours. 


CONVEYANCE  OF  THOUGHT  57 

After  sending  a  message  the  young  operator  switches  on  to 
the  receiver,  which  is  contained  in  a  metal  box  about  the  size 
of  a  valise.  The  same  perpendicular  wire  from  the  masthead 
serves  to  receive  messages  as  well  as  to  send  them,  but  the  in- 
struments within  the  office  for  sending  and  for  receiving  are 
quite  different. 

The  receiving  apparatus  is  kept  in  a  lead  box  to  protect  it 
from  the  influence  of  the  sending  machine,  which  rests  be- 
side it  on  the  table.  You  can  easily  believe  that  a  receiver 
sensitive  enough  to  record  impulses  from  a  point  eighteen  miles 
away,  might  be  disorganized  if  these  impulses  came  from  a  dis- 
tance of  two  or  three  feet.  But  the  lead  box  keeps  out  these 
nearby  vibrations. 

The  coherer  is  the  part  of  the  receiving  apparatus  which 
makes  wireless  telegraphy  possible,  and  to  it  more  than  to  any- 
thing else  has  Marconi  given  his  attention.  He  did  not  make 
the  first  coherer,  but  he  made  the  first  one  that  was  practically 
useful,  and  to  this  great  and  important  invention  he  owes  his 
success. 

I  will  try  to  give  a  clear  idea  of  what  this  coherer  is  like, 
and  why  it  is  so  important.  It  consists  of  a  tube  made  of 
glass,  about  the  thickness  of  a  thermometer  tube,  and  about 
two  inches  long.  It  seems  absurd  that  so  tiny  and  simple  an 
affair  can  come  as  a  benefit  to  all  mankind ;  yet  the  chief  virtue 
of  Marconi's  invention  lies  here  in  this  fragile  coherer.  But 
for  this,  induction  coils  would  snap  their  messages  in  vain,  for 
none  could  read  them.  In  each  end  of  this  tube  there  is  a 
silver  plug,  the  two  plugs  nearly  meeting  within  the  tube.  In 
the  narrow  space  between  the  plugs  nestle  several  hundred 
minute  fragments  of  nickel  and  silver,  the  finest  dust,  siftings 
through  silk,  and  these  enjoy  the  strange  property  (as  Marconi 
discovered)  of  being  alternately  very  good  conductors  and  very 
bad  conductors  for  the  Hertzian  waves — very  good  conductors 
when  welded  together  by  the  passing  current  to  a  continuous 
metal  path,  very  bad  conductors  when  they  fall  apart  under  a 
blow  from  the  electrical  tapper  which  is  a  part  of  the  receiving 
apparatus.  One  end  of  the  coherer  is  connected  with  the  wire 
which  hangs  from  the  mast  outside,  the  other  with  the  earth 


58  ACHIEVEMENTS  IN  SCIENCE 

and  also  with  a  home  battery  that  works  the  tapper  and  the 
Morse  printing  instrument. 

And  the  practical  operation  is  this:  A  single  vibration 
comes  through  the  ether,  down  the  wire  and  into  the  coherer, 
causing  the  particles  of  metal  to  stick  together  or  cohere 
(hence  the  name).  Then  the  Morse  instrument  prints  a  dot, 
and  the  tapper  strikes  its  little  hammer  against  the  glass  tube. 
That  blow  jars  apart  or  decoheres  the  particles  of  metal,  and 
stops  the  current  of  the  home  battery.  And  each  successive 
impulse  through  the  ether  produces  the  same  curious  coherence 
and  decoherence,  and  the  same  printing  of  dot  or  dash.  The 
impulses  through  the  ether  would  never  be  strong  enough  of 
themselves  to  work  the  printing  instrument  and  the  tapper, 
but  they  are  strong  enough  to  open  and  close  a  valve  (the 
metal  dust),  which  lets  in  or  shuts  out  the  stronger  current  of 
the  home  battery — all  of  which  is  simple  enough  after  some 
one  has  taught  the  world  how  to  do  it. 

"  We  have  telegraphed  twenty-five  miles  from  a  ship  to  the 
shore,"  said  Dr.  Erskine-Murray,  assistant  to  Marconi,  "and 
in  that  distance  the  earth's  dip  amounts  to  about  five  hundred 
feet.  If  the  curvature  counted  against  us  then,  the  messages 
would  have  passed  some  hundreds  of  feet  over  the  receiving 
station;  but  nothing  of  the  sort  happened.  So  we  feel  reason- 
ably confident  that  these  Hertzian  waves  follow  around  smoothly 
as  the  earth  curves." 

"  And  you  can  send  messages  through  hills,  can  you  not, 
and  in  all  kinds  of  weather  ? " 

"  Easily.    We  have  done  so  repeatedly." 

"  Then  if  neither  land  nor  sea  nor  atmospheric  conditions 
can  stop  you,  I  don't  see  why  you  can't  send  messages  to  any 
distance." 

"  So  we  can,"  said  the  electrician — "  so  we  can,  given  a  suffi- 
cient height  of  wire.  It  has  become  simply  a  question  now 
how  high  a  mast  you  are  willing  to  erect.  If  you  double  the 
height  of  your  mast,  you  can  send  a  message  four  times  as  far. 
If  you  treble  the  height  of  your  mast,  you  can  send  a  message 
nine  times  as  far,  and  so  on  up.  To  start  with,  you  may 
assume  that  a  wire  suspended  from  an  eighty-foot  mast  will 


CONVEYANCE  OF  THOUGHT  6& 

send  a  message  twenty  miles.  We  are  doing  about  that 
here." 

"  Then  a  mast  one  hundred  and  sixty  feet  feet  high  would 
send  a  message  eighty  miles." 

"  Exactly." 

"  And  a  mast  three  hundred  and  twenty  feet  high  would 
send  a  message  three  hundred  and  twenty  miles ;  a  mast  six 
hundred  and  forty  feet  high  would  send  a  message  1,280  miles ; 
and  a  mast  1,280  feet  high  would  send  a  message  5,120  miles  ? " 

"That's  right.  So  you  see  if  there  were  another  Eiffel 
Tower  in  New  York,  it  would  be  possible  to  send  messages  to 
Paris  through  the  ether  and  get  answers  without  ocean  cables." 

"  Do  you  really  think  that  would  be  possible  ? " 

"  I  see  no  reason  to  doubt  it,"  answered  Dr.  Erskine-Murray. 
"  What  are  a  few  thousand  miles  to  this  wonderful  ether,  which 
brings  us  our  light  every  day  from  millions  of  miles  away  ? " 

One  of  the  greatest  of  present  difficulties  is  that  of  secur- 
ing secrecy  in  the  transmission  of  these  ethereal  messages. 
The  vibrations  from  the  perpendicular  wires  are  transmitted 
equally  well  in  every  direction,  exactly  as  circular  waves  are 
produced  when  a  stone  is  thrown  in  the  water.  Therefore  any 
one  may  set  up  a  receiver  anywhere  within  the  range  of  the 
waves,  and  take  the  message.  Thus,  in  times  of  war,  commu- 
nications between  battleships  or  armies  might  be  at  the  mercy 
of  any  one  who  had  a  Marconi  receiver,  although,  of  course, 
generals  and  admirals  might  use  cipher  despatches. 

Marconi  realizes  the  very  great  importance  of  sending  mes- 
sages in  one  and  only  one  direction.  Light  waves  can  be  re- 
flected by  a  mirror,  and  thrown  upon  one  particular  spot. 
Every  boy  who  has  played  in  school  with  a  bit  of  looking-glass 
knows  this  fact  well.  Now,  electricity,  which  is  also  produced 
by  vibrations  in  the  ether,  can  also  be  reflected.  Marconi  has 
been  experimenting  with  a  copper  reflector,  by  means  of  which 
he  throws  a  peculiar  kind  of  electrical  wave  directly  through 
space  to  the  distant  receiver.  In  this  way  a  message  may  be 
aimed  in  any  direction  by  simply  turning  the  reflector  a  little, 
and  no  one  but  the  man  at  the  receiver  can  know  what  is  being 
sent.  This  exceedingly  important  feature  of  the  work  is,  how- 


60  ACHIEVEMENTS  IN  SCIENCE 

ever,  still  in  an  experimental  stage,  and  the  inventor  who  is 
successful  in  making  a  really  practical  reflecting  apparatus  will 
win  a  fortune. 

The  practical  uses  of  wireless  telegraphy  are  many.  In 
December,  1898,  the  English  lightship  service  authorized  the 
establishment  of  wireless  communication  between  the  South 
Foreland  lighthouse  at  Dover  and  the  East  Goodwin  lightship, 
twelve  miles  distant.  This  was  installed  in  the  usual  way  with- 
out difficulty,  and  has  been  in  operation  ever  since,  the  light- 
ship keepers  learning  to  use  the  instruments  in  a  few  days. 
And  before  the  apparatus  had  been  up  six  months  several 
warnings  of  wrecks  and  vessels  in  distress  reached  shore,  when, 
but  for  the  Marconi  signals,  nothing  of  the  danger  would  have 
been  known. 

Another  application  of  wireless  telegraphy  that  promises  to 
become  important  is  the  signaling  of  incoming  and  outgoing 
vessels.  With  Marconi  stations  all  along  the  coast,  it  would 
be  possible  for  all  vessels  within  twenty-five  miles  of  shore  to 
make  their  presence  known  and  to  send  or  receive  communica- 
tions. 

So  apparent  are  the  advantages  of  such  a  system  that  in 
May,  1898,  Lloyds  began  negotiations  with  the  Wireless  Tele- 
graph Company  for  setting  up  instruments  at  various  Lloyds 
stations ;  and  a  preliminary  trial  was  made  between  Bally-castle 
and  Rathlin  Island  in  the  north  of  Ireland.  The  distance  sig- 
naled was  seven  and  a  half  miles,  with  a  high  cliff  intervening 
between  the  two  positions,  and  the  results  of  many  trials  were 
absolutely  satisfactory. 

We  come  now  to  that  historic  week  in  March,  1899,  when 
the  system  of  wireless  telegraphy  was  put  to  its  most  severe 
test  in  experiments  across  the  English  Channel  between  Dover 
and  Boulogne.  These  were  undertaken  by  request  of  the 
French  Government,  which  was  considering  a  purchase  of  the 
rights  to  the  invention  in  France.  At  five  o'clock  on  the  after- 
noon of  Monday,  March  27th,  everything  being  ready,  Marconi 
pressed  the  sounding-key  for  the  first  cross-channel  message. 
The  transmitter  sounded,  the  sparks  flashed,  and  a  dozen  eyes 
looked  out  anxiously  upon  the  sea.  Would  the  message  carry 


CONVEYANCE  OF  THOUGHT  61 

all  the  way  to  England?    Thirty-two  miles  seemed  a  long 
way! 

Marconi  transmitted  deliberately  a  short  message,  telling 
the  Englishmen  that  he  was  using  a  two-centimetre  spark,  and 
signing  three  V's  at  the  end.  Then  he  stopped,  and  the  room 
was  silent  with  a  straining  of  ears  for  some  sound  from  the  re- 
ceiver. A  moment's  pause,  and  then  it  came  briskly,  and  the 
tape  rolled  off  its  message.  There  it  was,  short  and  common- 
place enough,  yet  vastly  important,  since  it  was  the  first  wire- 
less message  sent  from  England  to  the  Continent :  First  "  V," 
the  call ;  then  "  M,"  meaning  "  Your  message  is  perfect " ;  then, 
"  Same  here,  2  c  m  s.  V  V  V.,"  the  last  being  an  abbreviation 
for  two  centimetres  and  the  conventional  finishing  signal. 

And  so  the  thing  was  done;  a  marvelous  new  invention 
was  come  into  the  world  to  stay. 

On  the  following  Wednesday  Marconi  did  a  graceful  thing 
by  sending  a  complimentary  message  to  M.  Branly  (in  Paris), 
the  inventor  of  the  original  coherer,  which  Marconi  had  im- 
proved upon.  He  also  sent  a  long  message  to  the  Queen  of 
Italy.  More  recently  Marconi  sent  signal  messages  between 
England  and  Nova  Scotia.  Ships  now  exchange  word-mes- 
sages with  each  other  on  the  ocean. 

Mr.  Moffett  asked  one  of  Marconi's  chief  engineers  if  there 
was  not  a  great  saving  by  the  wireless  system  over  cables. 

"Judge  for  yourself,"  was  the  answer.  "Every  mile  of 
deep-sea  cable  costs  about  $750;  every  mile  for  the  land  ends 
about  $1,000.  We  save  all  that,  also  the  great  expense  of 
keeping  a  cable  steamer  constantly  in  commission  making  re- 
pairs and  laying  new  lengths.  All  we  need  is  a  couple  of  masts 
and  a  little  wire.  The  wear  and  tear  is  practically  nothing. 
The  cost  of  running  is  simply  the  cost  of  home  batteries  and 
operators'  keep." 

"  How  fast  can  you  transmit  messages  ? " 

"  Just  now  at  the  rate  of  about  fifteen  words  a  minute ;  but 
we  shall  do  better  than  that,  no  doubt,  with  experience." 

"  Do  you  think  there  is  much  field  for  the  Marconi  system 
in  overland  transmission  ?  " 

"  In  certain  cases,  yes.     For  instance,  where  you  can't  ret 


i 


62  ACHIEVEMENTS  IN  SCIENCE 

the  right  of  way  to  put  up  wires  and  poles.  What  is  a  dis- 
obliging farmer  going  to  do  if  you  send  messages  right  through 
his  farm,  barns  and  all  ?  He  can't  sue  the  Hertzian  waves  for 
trespass,  can  he  ?  Then  see  the  advantage,  in  time  of  war,  for 
quick  communication,  and  no  chance  that  the  enemy  may  cut 
your  wires." 

"  But  they  may  read  your  messages." 

"  That  is  not  so  sure,  for  besides  the  possibility  of  directing 
the  waves  with  reflectors,  Marconi  is  now  engaged  in  most 
promising  experiments  in  syntony,  which  I  may  describe  as  the 
electrical  tuning  of  a  particular  transmitter  to  a  particular  re- 
ceiver, so  that  the  latter  will  respond  to  the  former  and  no 
other,  while  the  former  will  influence  the  latter  and  no  other. 
That,  of  course,  is  a  possibility  in  the  future,  but  it  may  soon 
be  realized.  There  are  even  some  who  maintain  that  there 
may  be  produced  as  many  separate  sets  of  transmitters  and  re- 
ceivers capable  of  working  together  as  there  are  separate  sets 
of  Yale  locks  and  keys.  In  that  event,  any  two  private  indi- 
viduals might  communicate  freely  without  fear  of  being  under- 
stood by  others.  There  are  possibilities  here,  granting  a  limit- 
less number  of  distinct  tunings  for  transmitter  and  receiver, 
that  threaten  our  whole  telephone  system — I  may  add,  our 
whole  newspaper  system." 

"  Our  newspaper  system  ? " 

"  Certainly ;  the  news  might  be  ticked  off  tapes  every  hour 
right  into  the  houses  of  all  subscribers  who  had  receiving  in- 
struments tuned  to  a  certain  transmitter  at  the  news-distribut- 
ing station.  Then  the  subscriber  would  have  merely  to  glance 
over  their  tapes,  and  they  would  learn  what  was  happening  in 
the  world." 

"  Will  the  wireless  company  sell  its  instruments  ? " 

"  No,  it  will  rent  them  on  a  royalty,  as  telephone  companies 
do,  except,  of  course,  where  rights  for  a  whole  country  are 
absolutely  disposed  of." 

There  was  further  talk  of  the  possibilities  in  wireless  teleg- 
raphy, and  of  the  services  Marconi's  invention  may  render  in 
coming  wars. 

"If  you  care  to  stray  a  little  into  the  realm  of  speculation," 


CONVEYANCE  OF  THOUGHT  63 

said  the  engineer,  "  I  will  point  out  a  rather  sensational  r61e 
that  our  instruments  might  play  in  military  strategy.  Suppose, 
for  instance,  you  Americans  were  at  war  with  Spain,  and 
wished  to  keep  close  guard  over  Havana  harbor  without  send- 
ing your  fleet  there.  The  thing  might  be  done  with  a  single 
fast  cruiser  in  this  way :  Supposing  a  telegraphic  cable  laid 
from  Key  West,  and  ending  at  the  bottom  of  the  sea  a  few 
miles  out  from  the  harbor.  And  supposing  a  Marconi  receiv- 
ing instrument,  properly  protected,  to  be  lying  there  at  the 
bottom  in  connection  with  the  cable.  Now,  it  is  plain  that  this 
receiver  will  be  influenced  in  the  usual  way  by  a  Marconi  trans- 
mitter aboard  the  cruiser,  for  the  Hertzian  waves  pass  well 
enough  through  water.  With  this  arrangement,  the  captain  of 
your  cruiser  may  now  converse  freely  with  the  admiral  of  the 
fleet  at  Key  West  or  with  the  President  himself  at  Washing- 
ton, without  so  much  as  quitting  his  deck.  He  may  report 
every  movement  of  the  Spanish  warships  as  they  take  place, 
even  while  he  is  following  them  or  being  pursued  by  them.  So 
long  as  he  keeps  within  twenty  or  thirty  miles  of  the  sub- 
merged cable-end,  he  may  continue  his  communications,  may 
tell  of  arrivals  and  departures,  of  sorties,  of  loading  transports, 
of  filling  bunkers  with  coal,  and  a  hundred  other  details  of 
practical  warfare.  In  short,  this  captain  and  his  innocent  look- 
ing cruiser  may  become  a  never-closing  eye  for  the  distant 
American  fleet.  And  it  needs  but  little  thought  to  see  how 
easily  an  enemy  at  such  disadvantage  may  be  taken  unawares 
or  be  led  into  betraying  important  plans." 

And  here  we  may  leave  this  fascinating  subject,  in  the  hope 
that  we  have  seen  clearly  what  already  is,  and  with  a  half  dis- 
cernment of  what  is  yet  to  be. 


CONVEYANCE  OF  THOUGHT 


Sound 

By  ELISHA  GRAY 

VIBRATION  is  an  oscillation,  or  shaking  to  and  fro,  made 
by  a  stationary  body  (like  a  pendulum,  or  a  stretched 
wire)  when  disturbed  from  its  equilibrium  or  rest.  When  this 
motion  is  slow — as  a  pendulum — it  is  called  oscillation;  when 
rapid — as  of  a  wire  or  tuning-fork — it  is  called  vibration.  The 
latter  term  is  used  also  in  describing  the  action  of  a  disturbed 
fluid — as  of  water,  air,  or  ether — when  it  results  in  a  wave- 
motion,  a  phenomenon  so  familiar  that  it  needs  no  definition. 
The  effects  of  Sound,  Light,  and  Heat  are  all  produced  through 
vibrations  of  the  medium  transmitting  the  disturbing  force. 
We  will  begin  with  the  first  named. 

Sound  is  one  of  the  important  mediums  through  which  the 
inner  man  communicates  with  the  outer  world.  It  may  be  de- 
fined as  Motion  or  Vibration,  in  its  objective  or  outer  manifes- 
tations, and  as  Sensation  in  its  effect  upon  our  consciousness 
through  the  medium  of  the  organs  of  hearing. 

There  are  many  avenues  to  the  brain  that  are  in  touch  with 
the  outer  world  through  the  medium  of  the  five  senses. 
Through  all  of  these  avenues  the  same  general  vehicle  is  used 
to  carry  intelligence  to  the  brain  of  the  percipient — to  wit, 
motion. 

It  is  motion  of  the  optic  nerve  that  carries  to  the  brain  the 
sensation  of  light.  It  is  motion  of  the  gustatory  nerve  that 
carries  to  the  brain  the  sensation  of  taste.  It  is  motion  of  the 
olfactory  nerve  that  carries  to  the  brain  the  sensation  of  smell. 
It  is  motion  of  the  nerves  of  feeling  that  carries  the  sense  of 

64 


CONVEYANCE  OF  THOUGHT  65 

touch ;  and  it  is  a  motion  of  the  auditory  nerve  that  gives  us 
the  sensation  of  sound. 

Nothing  but  sound  can  be  transmitted  through  the  auditory 
nerve,  and  nothing  but  light  through  the  optic  nerve.  The 
same  is  true  of  the  other  avenues  to  the  brain :  you  cannot 
smell  with  your  tongue  or  taste  with  your  nose,  although  the 
sense  of  taste  and  smell  are  very  closely  allied ;  that  is,  we 
often  taste  and  smell  at  the  same  time,  but  attribute  the  sensa- 
tion all  to  taste.  Put  a  cinnamon  drop  on  your  tongue  and 
hold  your  nose  and  you  will  taste  only  sugar.  You  get  the 
taste  of  cinnamon  only  when  the  nasal  passages  are  open.  We 
really  taste  and  smell  at  the  same  time,  in  some  instances,  and 
call  it  all  taste.  Each  special  nerve  has  its  special  use.  If  we 
have  lost  one  of  these  highways  between  the  outer  world  and 
the  inner  self,  by  so  much  we  are  dead  to  physical  things. 

All  the  phenomena  of  sound,  outside  of  the  point  where  we 
perceive  it,  are  simply  motions  of  some  character.  The  different 
kinds  of  sound  are  infinite,  but  each  sensation  of  sound  that 
differs  from  another  has  its  correlative  in  the  air  outside  of  the 
ear  as  a  peculiar  form  of  motion.  For  instance,  if  some  one 
out  of  sight,  but  not  out  of  hearing,  should  sound  a  note  on  a 
violin,  you  would  say  that  you  heard  a  violin ;  but  if  some  one 
should  sound  a  note,  of  the  same  pitch,  on  an  organ,  you  would 
say  that  you  heard  an  organ.  What  is  the  difference  ?  Simply 
that  the  kind  or  quality  of  the  motion  made  by  the  violin  differs 
from  that  of  the  organ ;  hence  the  difference  of  the  sensation. 
What  this  difference  is  will  be  fully  explained  in  its  proper 
place. 

Let  us  now  go  back  and  follow  out  the  course  of  a  single 
sound-impulse  from  its  source  to  the  ear,  and  through  it  to  the 
brain — the  seat  of  sensation. 

Let  us  fill  a  soap-bubble  with  oxygen  and  hydrogen  gases 
in  the  proportion  of  two  parts  of  hydrogen  to  one  of  oxygen. 
If  we  ignite  it  the  result  will  be  an  explosion.  When  the  igni- 
tion takes  place  there  is  a  sudden  generation  of  heat,  which 
suddenly  expands  the  air,  causing  it  to  be  highly  rarefied  at  the 
point  of  explosion.  The  air  immediately  surrounding  it  is 
driven  violently  outward  in  every  direction.  The  first  layer  of 


>66  ACHIEVEMENTS  IN  SCIENCE 

air-particles,  surrounding  the  bubble,  is  driven  against  the  sec- 
ond and  then  swings  back  to  its  place,  for  the  force  that  drove 
it  outward  is  no  longer  present.  The  second  layer  swings 
against  the  third  and  the  third  against  the  fourth,  and  so  on ; 
each  layer  after  making  its  excursion  outward  returns  to  its 
original  position.  The  air-particles  are  not  fired  at  the  ear  as 
from  a  gun ;  they  simply  vibrate  to  and  fro.  The  sound-pulse 
moves  outward  like  an  expanding  globe  at  the  rate  of  about 
1,100  feet  per  second  in  air,  the  speed  depending  upon  the 
medium  through  which  it  travels. 

Some  notion  of  the  movement  of  a  sound-pulsation  may  be 
had  by  watching  the  expanding  ring  made  by  a  pebble  when 
dropped  into  a  pond  of  smooth  water.  A  still  clearer  idea  may 
be  had  by  laying  a  number  of  billiard-balls  in  a  groove,  so  that 
they  are  in  close  contact.  Now  tap  on  one  of  the  end  balls 
sharply  and  watch  the  effect.  None  of  the  balls  seem  to  have 
changed  position  except  the  end  one,  opposite  from  the  one 
that  received  the  blow.  This  one  has  rolled  away  from  the 
others.  The  first  ball  struck  delivered  its  blow  to  the  second, 
and  so  on  to  the  last.  This  one,  having  nothing  to  deliver  its 
blow  to,  rolls  away  under  the  impetus  given  to  it  by  the  ball 
next  to  it.  This  is  precisely  what  takes  place  in  the  air,  only 
with  balls  infinitely  small,  as  compared  with  the  billiard-balls. 
Each  ball  has  made  a  pendulous  motion ;  it  has  moved  forward 
a  short  space  and  returned  to  its  original  position.  The  dis- 
tance it  has  moved  forward  and  back  is  called  the  amplitude 
(largeness — size)  of  its  motion  or  vibration,  and,  other  things 
being  equal,  the  loudness  of  a  sound  varies  as  the  square  of  the 
amplitude  of  the  vibratory  impulse. 

Starting  again  with  our  soap-bubble,  from  the  point  of 
explosion:  the  same  impulse  moves  in  every  direction — like 
light  from  a  single  luminous  point — through  the  air,  but  pro- 
duces no  sensation  till  it  strikes  an  ear.  The  membrane  of  the 
ear  is  made  to  vibrate  or  swing  back  and  forth,  which,  in  turn, 
moves  the  inner  mechanism  of  the  ear — for  it  is  a  mechanism, 
and  a  most  wonderful  one — which  finally  communicates  its 
motion  to  the  auditory  nerve,  which  reaches  into  the  brain, 
where  the  motion  is  translated  into  a  sensation  that  we  call 


CONVEYANCE  OF  THOUGHT  67 

Sound.  What  is  this  mysterious  blending  between  the  activi- 
ties of  the  outer  world  and  the  sense-perception  of  the  inner 
consciousness  ?  All  the  combined  wisdom  of  philosophers  and 
sages  has  never  solved  the  problem.  Much  has  been  written, 
but  no  explanation,  only  words,  words,  words.  We  have  to  be 
satisfied  with  studying  the  phenomena  only,  of  natural  law,  for 
that  is  all  we  can  really  know  about  it.  We  perceive  the  facts, 
but  cannot  explain  how  the  physical  is  translated  into  mental 
consciousness. 

Sound  is  transmitted  either  through  gases,  liquids,  or  solids, 
but  the  velocity  is  determined  by  the  elasticity  of  the  medium 
through  which  it  is  transmitted.  Numerous  experiments  have 
been  made  to  determine  the  velocity  of  sound  when  transmitted 
through  different  media,  and  long  tables  on  this  subject  may  be 
found.  The  following  table  will  give  a  general  idea  of  the 
velocity  of  sound  through  solids,  liquids,  and  gases : 

The  velocity  through  air,  1,100  feet  per  second. 
The  velocity  through  water,  over  four  times  that  of  air. 
The  velocity  through  pine  wood,  ten  times  that  of  air. 
The  velocity  through  iron,  seventeen  times  that  of  air. 

These  figures  are  only  approximately  correct,  as  the  velocity 
of  sound  in  gases  varies  with  changes  of  temperature.  Again, 
a  loud  sound  travels  faster  than  a  feeble  one.  A  striking  in- 
stance of  this  fact  is  shown  in  an  experiment  made  by  some 
Arctic  explorers.  Sounds,  even  moderate  ones,  are  heard  to 
comparatively  great  distances  over  smooth  ice.  A  cannon  was 
fired,  and  the  observer,  who  was  quite  a  distance  from  the  gun, 
heard  the  boom  of  the  cannon  before  he  heard  the  order  to  fire, 
which  of  course,  was  given  first. 

Sound  cannot  be  transmitted  through  a  vacuum,  as  shown 
by  the  following  familiar  experiment  made  by  a  philosopher 
named  Hawksbee  as  far  back  as  1705.  Place  a  bell  that  is 
operated  by  a  clockwork  inside  of  the  receiver  of  an  air-pump. 
This  receiver  is  a  large  bell-glass,  ground  to  make  an  air-tight 
fit  on  the  bedplate  of  the  air-pump.  Suspend  the  bell  inside 
the  receiver,  by  some  kind  of  cord  that  will  not  transmit  sound, 
and  then  set  it  to  ringing.  At  first  it  will  ring  as  loudly  as 


68  ACHIEVEMENTS  IN  SCIENCE 

though  it  were  in  the  open  air.  Now,  work  the  pump  and  ex- 
haust the  air.  The  sound  will  grow  fainter  until  a  nearly  per- 
fect vacuum  is  obtained,  when  the  sound  will  cease,  although 
the  hammer  is  still  striking  the  bell  the  same  as  at  first.  Now 
let  the  air  in  and  the  ringing  is  heard  again. 

Reasoning  from  the  above  experiment,  one  should  expect 
that  sounds  would  not  be  as  loud  on  high  mountains  as  down 
on  the  sea-level.  This  is  found  to  be  the  case,  because  the  air 
at  very  high  elevations  is  much  less  dense  and  there  are  fewer 
air  molecules  in  a  given  area  to  strike  upon  the  drum  of  the  ear. 

For  the  same  reason  sound  will  be  carried  farther  and  seem 
louder  on  some  days  than  others.  When  the  barometer  is  high 
it  shows  that  the  air  is  dense,  and  dense  air  is  a  better  medium 
for  sound  transmission  than  rarefied  air,  at  least  so  far  as  loud- 
ness  is  concerned.  The  experiment  with  the  bell  in  a  vacuum 
shows  that  sound  is  transmitted  only  through  material  of  some 
kind  that  may  be  made  manifest  to  our  senses.  It  also  shows 
that  matter,  as  we  understand  it,  is  not  necessary  for  the  trans- 
mission of  light  and  radiant  heat,  for  both  light  and  radiant 
heat  will  pass  through  the  vacuum,  when  the  bell  will  not 
sound,  as  readily  as  through  the  air. 

Sound  is  reflected  like  light.  It  may  be  focused  on  a  sin- 
gle point,  like  light  or  radiant  heat,  by  means  of  concave  re- 
flectors. It  tends  to  move  in  straight  lines,  but  will  in  a  degree 
go  around  an  object;  yet  a  large  object  casts  a  distinct  sound- 
shadow,  if  we  may  use  the  term.  If  we  throw  an  elastic  ball 
on  the  floor  with  considerable  force  it  will  rebound  at  the  same 
angle  at  which  it  was  moving  when  it  struck  the  floor.  The 
direction  it  was  moving  before  it  struck  is  called  the  angle  of 
incidence,  and  the  direction  it  moves  after  that  is  called  the 
angle  of  reflection.  Sound  and  light  obey  this  law.  Sound 
waves  are  reflected  from  a  polished  surface  the  same  as  light 
waves,  and  they  obey  the  same  laws  in  the  matter  of  focusing 
and  dispersion  that  light  does. 

A  striking  instance  of  sound  reflection  may  be  noticed  any 
time  during  the  passage  of  a  thunderstorm.  Whoever  has 
stood  on  a  mountain  top  towering  15,000  feet  above  the  sea  and 
from  this  view-point  of  a  cloudless  sky  and  bright  sunshine  has 


CONVEYANCE  OF  THOUGHT  69 

looked  down  upon  a  storm-cloud  hovering  far  below  against  the 
side  of  the  mountain,  and  stretching  far  across  the  valley,  has 
witnessed  a  scene  of  grandeur  that  no  language  can  adequately 
describe.  It  is  from  a  view  like  this  that  one  gets  an  accurate 
conception  of  cloud-form  as  it  really  is.  Great  billowy  moun- 
tains, whose  crests  are  tipped  with  purest  silver  and  whose 
shapes  are  as  multiformed  as  the  leaves  of  the  forest  and  as 
numberless  as  the  sands  of  the  desert ! 

A  storm-cloud  as  seen  from  above,  under  the  full  rays  of 
the  sun,  appears  to  be,  and  doubtless  is,  made  up  of  a  series  of 
clouds  that  may  or  may  not  touch  each  other.  During  the 
progress  of  the  storm  one  or  more  of  the  clouds  becomes  sur- 
charged from  time  to  time  with  electricity,  when  it  seeks  to 
establish  an  equilibrium,  by  discharging  into  the  earth  or  into 
another  cloud.  This  discharge  causes  a  great  sound  wave  to 
flow  out  from  the  point  of  disruption,  much  louder  than  the 
booming  of  the  heaviest  cannon,  and  it  travels,  as  we  have 
seen,  at  the  rate  of  1,100  feet  per  second  through  the  air  in  all 
directions.  Suppose  we  are  standing  one  mile  from  the  point 
of  disruption  in  the  cloud,  watching  the  operation  of  nature's 
great  electrical  power-plant.  We  see  a  flash  of  lightning,  and 
in  a  little  less  than  five  seconds  we  hear  the  thunder ;  and,  al- 
though there  has  been  only  a  single  report  like  the  firing  of  a 
cannon,  it  seems  to  us  to  be  a  great  many  following  each  other 
in  rapid  succession.  We  have  already  seen  that  a  sound  wave 
moves  out  like  an  expanding  globe  from  a  common  center, 
which  is  the  origin  of  the  sound  impulse.  A  part  of  the  wave 
coming  from  the  cloud  moves  in  a  direct  line  toward  the  ob- 
server. When  the  wave  strikes  his  ear  there  is  the  sensation 
of  an  explosion  of  great  power,  and  this  is  followed  by  others 
in  rapid  succession,  for  several  seconds,  each  succeeding  one 
growing  weaker  until  it  dies  out  in  what  seems  to  be  a  distant 
roll  of  thunder.  The  explanation  is  this :  Beyond  the  cloud 
where  the  discharge  took  place,  and  farther  away  from  the 
observer,  is  another  cloud  with  a  large  reflecting  surface,  and 
beyond  that  a  second,  a  third,  and  so  on,  it  may  be,  for  many 
miles.  Each  one  of  these  surfaces  reflects  back  to  the  ear  of 
the  observer  a  part  of  this  great  sonorous  impulse ;  but  as  a 


70  ACHIEVEMENTS  IN  SCIENCE 

part  of  the  wave  that  is  reflected,  is  reflected  from  the  succes- 
sive cloud  surfaces  that  are  farther  away,  and  no  two  of  them 
the  same,  the  reflected  sound  keeps  on  coming  to  the  ear  at 
disjointed  intervals,  because  the  distances  are  constantly  in- 
creasing and  not  uniform.  If  the  first  cloud  beyond  the  point 
of  explosion  is  five  hundred  and  fifty  feet  farther  away  from 
the  observer,  the  second  explosion,  or  the  first  reflected  explo- 
sion, will  occur  one  second  after  the  first ;  for  it  has  to  travel 
five  hundred  and  fifty  feet  away,  and  then  retrace  the  distance. 
So,  by  that  time,  the  original  wave  will  have  one-fifth  of  a  mile 
the  start.  This  is  the  cause  in  many  instances,  and  the  chief 
cause  in  most  cases,  of  the  phenomena  of  rolling  thunder. 


CONVEYANCE  OF  THOUGHT 


How  the  Telephone  Talks 

By  ELISHA  GRAY 

T^VERYBODY  knows  what  the  telephone  is,  because  it  is  in 
JJ/  almost  every  man's  house.  But  while  everybody  knows 
what  it  is,  there  are  very  few  (comparatively  speaking)  who 
know  how  it  works. 

When  any  one  utters  a  spoken  word,  the  air  is  thrown  into 
shivers  or  vibrations  of  a  peculiar  form,  and  every  different 
sound  has  a  different  form.  Therefore,  every  articulate  word 
differs  from  every  other  word,  not  only  as  a  shape  in  the  air, 
but  as  a  sensation  in  the  brain,  where  the  air  vibrations  have 
been  conducted  through  the  organ  of  hearing;  otherwise  we 
could  not  distinguish  between  one  word  and  another.  Every 
different  word  produces  a  different  sensation  because  there  is 
a  physical  difference,  as  a  shape  or  motion,  in  the  air  where  it 
is  uttered.  If  one  word  contains  1,000  simultaneous  air  motions 
and  another  1,500,  you  can  see  that  there  is  a  physical  or  me- 
chanical difference  in  the  air. 

The  construction  of  the  simplest  form  of  telephone  is  as 
follows :  Take  a  piece  of  iron  rod  one-half  or  three-quarters  of 
an  inch  long  and  one-quarter  inch  thick,  and  after  putting  a 
spool-head  on  each  end  to  hold  the  wire  in  place,  wind  it  full  of 
fine  insulated  copper  wire ;  fasten  the  end  of  this  spool  to  the 
end  of  a  straight-bar  permanent  magnet.  Then  put  the  whole 
into  a  suitable  frame,  and  mount  a  thin  circular  diaphragm 
(membrane  or  plate)  of  iron  or  steel,  held  by  its  edges,  so  that 
the  free  end  of  the  spool  will  come  near  to  but  not  touch  the 
center  of  the  diaphragm.  This  diaphragm  must  be  held  rigidly 
at  the  edges. 

71 


: 


72  ACHIEVEMENTS  IN  SCIENCE 

Now  if  the  two  ends  of  the  insulated  copper  wires  are 
brought  out  to  suitable  binding-screws,  the  instrument  is  done. 

The  permanent  steel  magnet  serves  a  double  purpose. 
When  the  telephone  was  first  used  commercially,  the  instru- 
ment now  used  as  a  receiver  was  also  used  as  a  transmitter. 
As  a  transmitter  it  is  a  dynamo-electric  machine.  Every  time 
the  iron  diaphragm  is  moved  in  the  magnetic  field  of  the  pole 
of  the  permanent  magnet,  which  in  this  case  is  the  free  end  of 
the  spool  (the  iron  of  the  spool  being  magnetic  by  contact  with 
the  permanent  magnet),  there  is  a  current  set  up  in  the  wire 
wound  on  the  spool ;  a  short  impulse,  lasting  only  as  long  as 
the  movements  lasts.  The  intensity  of  the  impulse  will  depend 
upon  the  amplitude  and  quickness  of  the  movement  of  the  dia- 
phragm. If  there  is  a  long  movement  there  will  be  a  strong 
current,  and  vice  versa.  If  a  sound  is  uttered,  and  even  if  the 
multitude  of  sounds  that  are  required  to  form  a  word,  be  spoken 
to  the  diaphragm,  the  latter  partakes  in  kind  of  the  air  motions 
that  strike  it.  It  swings  or  vibrates  in  the  air,  and  if  it  is  a 
perfect  diaphragm  it  moves  exactly  as  the  air  does,  both  as  to 
amplitude  and  complexity  of  movement. 

All  these  complex  motions  are  communicated  by  the  air  to 
the  diaphragm,  and  the  diaphragm  sets  up  electric  currents  in 
the  wire  wound  on  the  spool,  corresponding  exactly  in  number 
and  form,  so  that  the  current  is  molded  exactly  as  the  air  waves 
are.  Now,  if  we  connect  another  telephone  in  the  circuit,  and 
talk  to  one  of  them,  the  diaphragm  of  the  other  will  be  vibrated 
by  the  electric  current  sent,  and  caused  to  move  in  sympathy 
with  it  and  make  exactly  the  same  motions  relatively,  both  as 
to  number  and  amplitude. 

It  will  be  plain  that  if  the  receiving  diaphragm  is  making 
the  same  motions  as  the  transmitting  diaphragm,  it  will  put  the 
air  in  the  same  kind  of  motion  that  the  air  is  in  at  the  trans- 
mitting end,  and  will  produce  the  same  sensation  when  sensed 
by  the  brain  through  the  ear.  If  the  air  motion  is  that  of  any 
spoken  word,  it  will  be  the  same  at  both  ends  of  the  line,  except 
that  it  will  not  be  so  intense  at  the  receiving  end ;  it  is  the 
same  relatively.  And  this  is  how  the  telephone  talks. 

I  have  said  that  the  permanent  magnet  had  two  functions. 


CONVEYANCE  OF  THOUGHT  73 

In  the  case  of  the  transmitter  it  is  the  medium  through  which 
mechanical  is  converted  into  electrical  energy.  It  corresponds 
to  the  field  magnet  of  the  dynamo,  while  the  diaphragm  corre- 
sponds to  the  revolving  armature,  and  the  voice  is  the  steam 
engine  that  drives  it.  In  the  second  place,  it  puts  a  tension  on 
the  diaphragm  and  also  puts  the  molecules  of  the  iron  core  of 
the  magnet  in  a  state  of  tension  or  magnetic  strain,  and  in  that 
condition  both  the  molecules  and  the  diaphragm  are  much  more 
sensitive  to  the  electric  impulses  sent  over  the  wire  from  the 
transmitter.  At  the  present  day  this  form  of  telephone  is  used 
only  as  a  receiver. 

Transmitters  have  been  made  in  a  variety  of  forms,  but 
there  are  only  two  generic  methods  of  transmission.  One  is 
the  magneto  method — the  one  we  have  described — and  the 
other  is  effected  by  varying  the  resistance  of  a  battery  current. 
The  former  will  work  without  a  battery,  as  the  voice  acting  on 
the  wire  around  the  magnet  through  the  diaphragm  creates  the 
current ;  in  the  latter  the  current  is  created  by  the  battery  but 
molded  by  the  voice.  In  the  latter  method  the  current  passes 
through  carbon  contacts  that  are  moved  by  the  diaphragm. 
Carbon  is  the  best  substance,  because  it  will  bear  a  wider  sepa- 
ration of  contact  without  actually  breaking  the  current.  When 
carbon  points  are  separated  that  have  an  electric  current  pass- 
ing through  them,  there  is  an  arc  formed  on  the  same  principle 
as  the  electric  arc-light. 

Great  improvements  in  details  have  been  made  in  the  tele- 
phone since  its  first  use,  but  no  new  principles  have  been  dis- 
covered as  applied  to  transmission. 

We  have  spoken  in  another  place  regarding  the  various 
claimants  to  the  invention  of  the  telephone,  but  here  is  one  that 
has  been  overlooked.  A  young  man  from  the  country  was  in 
a  telegraph  office  at  one  time  and  was  left  alone  while  the  opera- 
tor went  to  dinner.  Suddenly  the  sounder  started  up  and  rat- 
tled away  at  such  a  rate  that  the  countryman  thought  some- 
thing should  be  done.  He  leaned  down  close  to  the  instru- 
ment and  shouted  as  loudly  as  possible  these  words:  "The 
operator  has  gone  to  dinner."  From  what  we  know  now  of 
the  operation  of  the  telephone  I  have  no  doubt  but  that  he 


74  ACHIEVEMENTS  IN  SCIENCE 

transmitted  his  voice  to  some  extent  over  the  wire.  This 
young  man's  claims  have  never  been  put  forward  before,  and 
we  are  doing  him  tardy  justice.  But  his  claim  is  quite  as  good 
as  many  others  set  forth  by  people  who  think  they  invent, 
whenever  it  occurs  to  them  that  something  new  might  possibly 
be  done,  if  only  somebody  would  do  it.  And  when  that  some- 
body does  do  it,  they  lay  claim  to  it. 

In  the  early  days  of  the  telephone  it  was  not  supposed  that 
a  vocal  message  could  be  transmitted  to  a  very  great  distance. 
However,  as  time  went  on  and  experiments  were  multiplied, 
the  distance  to  which  one  could  converse  with  another  through 
a  wire  kept  on  increasing. 

In  these  days,  as  every  one  knows,  it  is  a  daily  occurrence 
that  business  men  converse  with  each  other,  telephonically,  for 
a  distance  of  1,000  miles  or  more;  in  fact,  it  is  possible  to 
transmit  the  voice  through  a  single  circuit  about  as  great  a  dis- 
tance as  it  is  possible  to  practically  telegraph.  This  leads  us 
to  speak  of  another  telegraphic  apparatus  which  we  have  not 
heretofore  mentioned,  and  that  is  the  telegraphic  repeater.  It 
is  a  common  notion  that  messages  are  sent  through  a  single 
circuit  across  the  continent,  but  this  is  not  the  case,  although 
the  circuits  are  very  much  longer  than  they  were  some  years 
ago.  The  repeater  is  an  instrument  that  repeats  a  message 
automatically  from  one  circuit  to  another.  For  instance,  if 
Chicago  is  sending  a  message  to  New  York  through  two  cir- 
cuits, the  division  being  in  Buffalo,  the  repeater  will  be  located 
at  Buffalo  and  under  the  control  of  both  the  operator  at  Chi- 
cago and  the  operator  in  New  York.  When  Chicago  is  send- 
ing, one  part  of  the  repeater  works  in  unison  with  the  Chicago 
key  and  is  the  key  to  the  New  York  circuit,  which  begins  at 
Buffalo.  When  New  York  is  sending,  the  other  part  of  the 
repeater  operates,  which  becomes  a  key  which  repeats  the  mes- 
sage to  the  Chicago  line.  In  this  way  the  practical  result  is 
the  same  as  though  the  circuit  were  complete  from  New  York 
to  Chicago.  At  the  present  day  some  of  the  copper  wires  and 
perhaps  some  of  the  larger  iron  wires  are  used  direct  from  Chi- 
cago to  New  York  without  repetition;  but  all  messages 
between  New  York  and  San  Francisco  are  automatically  re- 


CONVEYANCE  OF  THOUGHT  75 

peated  at  least  twice,  and  under  certain  conditions  of  weather 
oftener. 

The  repeater  was  a  very  delicate  instrument  and  had  to  be 
handled  by  a  skilled  operator.  Every  wire  must  be  in  its  place, 
or  the  instrument  would  fail  to  operate.  I  remember  on  one 
occasion  in  Cleveland  that  along  in  the  middle  of  the  night  the 
repeater  failed  to  work.  The  operator  knew  nothing  of  the 
principle  of  its  operation,  so  that  when  it  failed  he  had  to  ap- 
peal to  some  of  his  superiors. 

At  this  time  there  was  no  one  in  the  office  who  knew  how 
to  adjust  it,  so  they  had  to  send  up  to  the  house  of  the  superin- 
tendent and  arouse  him  from  his  sleep  and  bring  him  down  to 
the  office.  He  looked  under  the  table  and  found  that  one  of 
the  wires  had  loosened  from  its  binding-post  and  was  hanging 
down.  He  said  immediately,  "Here's  the  trouble;  I  should 
think  you  could  have  seen  it  yourself."  The  operator  replied, 
"  I  did  see  that,  but  I  didn't  think  one  wire  would  make  any 
difference."  He  learned  the  lesson  that  all  electricians  have 
had  to  learn — that  even  one  wire  makes  all  the  difference  in 
the  world.  But  this  operator  was  no  worse  in  that  respect  than 
some  of  his  superiors.  One  of  the  heads  of  the  Cleveland 
office  at  one  time  in  the  early  days  wanted  to  give  some  direc- 
tions to  the  office  at  Buffalo.  He  told  the  operator  at  the 
key  to  tell  Buffalo  so  and  so,  when  the  operator  replied :  "I 
can't  do  it;  Buffalo  has  his  key  open."  The  official  immedi- 
ately said  with  severity :  "  Tell  him  to  close  it."  He  forgot 
that  it  would  be  as  difficult  for  him  to  tell  him  to  close  it,  as  it 
would  have  been  to  have  sent  the  original  message. 

But  let  us  go  back  to  the  telephone.  While  it  is  possible 
to  send  a  message  from  New  York  to  San  Francisco  by  tele- 
graph, it  is  not  possible  to  telephone  that  distance,  because  as 
yet  no  one  has  been  able  to  devise  a  repeater  that  will  transfer 
spoken  words  from  one  line  to  another  satisfactorily.  But 
unless  the  printer  and  publisher  bestir  themselves,  some  one 
may  accomplish  the  feat  before  this  little  book  reaches  the 
reader.  If  this  proves  to  be  true,  let  the  writer  be  the  first  to 
congratulate  the  successful  inventor. 


LABOR-SAVING  MACHINERY 


The  Wonder-Working  Wheel 

By  ALFRED  RUSSEL  WALLACE 

THE  invention  and  partial  development  of  much  of  our 
modern  machinery  dates  from  the  last  century,  and  our 
most  advanced  appliances  for  the  manufacture  of  the  various 
textile  fabrics  and  hardware  are  mostly  improvements  of,  or 
developments  from,  the  older  machines.  These,  taken  in  con- 
nection with  the  great  improvements  in  steam  engines,  have 
multiplied  many  times  over  the  efficiency  of  human  labor,  but 
do  not  otherwise  specially  interest  us  here.  There  are,  how- 
ever, a  few  inventions  which  have  the  character  of  quite  new 
departures,  since  not  only  do  they  greatly  diminish  labor  but 
they  perform,  by  mechanical  contrivances,  operations  which 
had  been  supposed  to  be  beyond  the  power  of  machinery  to 
execute.  The  more  prominent  of  these  are  the  sewing  machine, 
the  typewriter,  and  the  combined  reaping,  threshing,  and  win- 
nowing machine,  of  which  a  brief  account  will  be  given. 

The  sewing  machine,  now  so  common,  exercised  the  inge- 
nuity of  mechanicians  for  a  long  period  before  it  arrived  at  suffi- 
cient perfection  to  be  suitable  for  general  use.  The  earlier 
machines  were  for  embroidering  only ;  then,  about  1790,  one  was 
made  for  stitching  shoes,  and  other  leather  work,  but  it  does 
not  seem  to  have  come  into  general  use.  A  crocheting  machine 
was  patented  in  1834;  somewhat  later  one  for  rough  basting; 
but  it  was  not  till  1846  that  the  first  effective  lock-stitch  sew- 
ing machine  was  made  by  Elias  Howe,  of  Cambridge,  Mass. 
Henceforth  sewing  machines  were  rapidly  improved  and  adapted 
to  every  variety  of  work ;  but  the  difficulty  of  the  problem  to 

76 


LABOR-SAVING  MACHINERY  11 

be  solved  is  shown  by  the  unusually  long  process  of  gradual 
development,  much  of  the  mechanical  talent  of  both  hemi- 
spheres being  occupied  for  nearly  a  century  before  the  various 
machines  so  familiar  to-day  were  perfected.  There  are  now 
special  machines  for  making  button-holes  and  for  sewing  on 
buttons,  for  carpet-sewing,  for  pattern-sewing,  for  leather  work, 
and  for  the  special  operations  required  in  the  making  and  re- 
pairing of  shoes.  Boot  and  shoe-making  by  machinery,  in  large 
factories,  has  entirely  grown  up  since  the  sewing  machine  was 
proved  to  be  adapted  for  almost  every  kind  of  sewing  work. 
As  a  result,  machine-made  boots  and  shoes  are  very  cheap,  but 
they  are  usually  of  inferior  quality  to  the  old  hand-made  arti- 
cles ;  and  first-class  work  is  quite  as  dear  as  it  was  fifty  or  sixty 
years  ago,  or  even  dearer. 

The  typewriter  is  a  still  later  invention,  and  though  per- 
haps less  difficult  than  the  sewing  machine,  yet  it  involves 
more  complex  motions  and  adjustments,  so  that  the  perfection 
it  has  so  quickly  attained  is  very  remarkable.  If  we  consider 
that  about  sixty  separate  types,  including  small  letters,  capi- 
tals, spaces,  stops,  etc.,  have  to  be  so  arranged  and  so  connected 
as  to  be  brought  in  any  order  whatever  to  a  definite  position, 
so  as  to  form  the  successive  letters  and  spaces  in  lines  of  printed 
characters,  and  then,  being  properly  inked,  must  be  brought 
into  contact  with  the  paper  so  as  to  produce  a  clear  impression, 
and  that  all  the  motions  of  the  machinery  required  must  be  the 
result  of  a  single  pressure  on  a  key  for  each  letter,  following 
one  another  as  rapidly  as  possible,  we  shall  have  some  idea  of 
the  difficulties  which  have  had  to  be  overcome.  Yet,  so  great 
are  the  resources  of  modern  mechanism,  and  the  ingenuity  of 
our  mechanists,  that  the  required  result  has  been  attained  in 
many  different  ways,  so  that  we  may  now  choose  between  half 
a  dozen  forms  of  typewriters,  no  one  of  which  seems  to  be  very 
markedly  superior  to  the  rest. 

More  important,  perhaps,  to  mankind  generally,  are  the 
harvesting  machines,  which  render  it  possible  to  utilize  one  or 
two  fine  days  to  secure  a  harvest.  Reaping  machines  have 
long  been  used  in  this  country,  and  they  were  followed  by  com- 
bined reapers  and  binders,  which  left  the  crop  ready  for  carting 


78  ACHIEVEMENTS  IN  SCIENCE 

to  the  barn.  But  this,  when  the  distance  was  great,  did  not 
save  the  grain  from  injury  by  wet,  besides  requiring  much 
labor  and  a  careful  process  of  stacking  to  preserve  it.  In 
America  a  harvesting  machine  has  been  brought  to  perfection, 
which  not  only  reaps  the  grain,  but  threshes  it,  winnows  it,  and 
delivers  it  into  sacks  ready  for  the  granary  or  the  market,  at 
one  operation.  This  machine,  with  two  men,  will,  in  one  fine 
day,  secure  the  crop  from  ten  or  fifteen  acres,  with  a  minimum 
of  labor.  In  the  great  wheat  fields  of  California  and  Australia, 
with  an  almost  uniformly  dry  climate  at  harvest  time,  it  is  this 
saving  of  labor  which  is  the  chief  consideration;  but  in  our 
treacherous  climate,  where  a  few  days'  delay  may  mean  the 
partial  or  complete  ruin  of  the  crop,  such  machines  will  be 
doubly  valuable  by  enabling  farmers  to  utilize  to  the  utmost 
every  fine  day  after  the  grain  is  ripe.  I  had  the  pleasure  of 
seeing  this  wonderful  machine  at  work  in  California  in  1887. 
It  was  propelled  by  sixteen  small  mules  harnessed  behind,  so 
as  not  to  be  in  the  way ;  but  steam  power  is  now  used.  Con- 
sidering what  it  effected,  it  was  wonderfully  light,  compact, 
and  simple ;  and  when  agriculture  is  treated  as  a  work  of  na- 
tional importance,  such  machines  will  render  us,  to  a  considera- 
ble extent,  independent  of  the  weather,  and  will  therefore  be- 
come a  necessity. 

The  three  mechanical  inventions  here  briefly  described  were 
conceived  in  the  first  half,  and  brought  to  perfection  in  the  second 
half  of  the  century.  They  each  mark  a  new  departure  in  human 
industry,  inasmuch  as  they  effect,  by  means  of  machinery  and 
at  one  operation,  what  had  previously  been  performed  by  human 
labor  directed  by  a  hand  or  arm  rendered  skillful  by  long  prac- 
tice, and  sometimes  requiring  several  distinct  operations. 
They  had  been  thus  performed  during  the  whole  preceding 
period  of  human  history,  or  so  long  as  the  particular  kind  of 
work  had  been  done ;  so  that,  though  of  less  general  use  and  of 
less  importance,  they  have  the  same  distinguishing  features 
which  we  have  found  to  characterize  our  new  methods  of  loco- 
motion. 

There  are,  of  course,  innumerable  other  remarkable  mechani- 
cal inventions  of  the  century  in  almost  every  department  of  in- 


LABOR-SAVING  MACHINERY 


79 


dustry — such  as  the  Jacquard  loom  for  pattern-weaving,  revolvers 
and  machine  guns,  iron  ships,  screw  propellers,  etc.;  while 
machinery  has  been  extensively  applied  to  watch-making,  screw- 
cutting,  nail-making,  printing,  and  a  hundred  other  purposes. 
But  none  of  these  are  of  very  high  importance  in  themselves, 
or  possess  the  special  characteristics  of  being  new  and  quite 
distinct  departures  from  what  has  been  done  before,  and  they 
cannot  therefore  rank  individually  among  those  greater  dis- 
coveries which  preeminently  distinguish  the  nineteenth  cen- 
tury. 


LABOR-SAVING  MACHINERY 


Printing,  Past  and  Present 

By  JOHN  TIMES 

THE  inquirers  into  the  origin  and  history  of  this  almost 
ubiquitous  "noble  craft  and  mystery,"  would  seem  to 
have  arrived  at  this  conclusion — that  it  is  difficult  to  say  at 
what  period  of  time  the  art  of  printing  did  not  exist.  The 
simplest  and  most  natural  mode  of  conveying  an  idea  is  by  the 
reproduction  of  similar  appearances  of  the  same  surface ;  and 
whether  this  be  by  a  hand  or  foot  upon  snow,  or  by  the  pres- 
sure of  wood  or  metal  upon  paper  or  vellum,  it  is  alike  printing. 
Accordingly,  we  find  evidence  that  nearly  four  thousand  years 
since,  a  rude  and  imperfect  method  was  certainly  practiced. 
First,  seals  were  impressed  upon  a  plastic  material ;  next,  sym- 
bols or  characters  were  stamped  upon  clay  in  forming  bricks 
(as  practiced  in  Babylon),  cylinders,  and  the  walls  of  edifices. 
Of  this  art,  Wilkinson  and  others  have  brought  examples  from 
Egypt ;  and  Rawlinson  and  Layard  from  the  ruins  of  the  buried 
cities  of  Asia.  Not  only  have  the  inscribed  bricks  been  found, 
but  the  wooden  stamps  with  which  they  were  impressed ;  of 
these,  numerous  specimens  are  in  the  British  Museum.  Here 
also  may  be  seen  several  instruments  presenting  a  singular  in- 
stance how  very  nearly  we  may  approach  to  an  important  dis- 
covery, and  yet  miss  it.  These  are  brass  or  bronze  stamps, 
having  on  their  faces  inscriptions  in  raised  characters  reversed. 
To  the  back  has  been  fastened  a  handle,  a  loop,  a  boss,  or  a 
ring.  One  use  of  these  stamps  has  evidently  been  to  print  the 
inscription,  by  aid  of  color,  upon  papyrus,  linen,  or  parchment ; 
and,  as  the  inscriptions  show  these  stamps  to  have  been  of  the 

80 


LABOR-SAVING  MACHINERY  81 

period  when  literature  had  become  one  of  the  pursuits  of  the 
great,  and  the  copying  of  books  was  a  slow  and  expensive  pro- 
cess, it  is  strange  that  the  Romans,  by  whom  these  signets 
were  used,  should  not  have  improved  upon  them  by  engraving 
whole  sentences  and  compositions  upon  blocks,  and  thence 
transferring  them  to  paper.  The  Chinese  printing  from  blocks 
at  this  day  closely  resembles  the  old  Roman ;  and  they  assert 
that  it  was  used  by  them  several  centuries  before  it  was  known 
in  Europe — in  fact,  fifty  years  before  the  Christian  era. 

A  vast  interval  elapses  between  the  above  attempts  and  the 
next  advance — engraving  pictures  upon  wooden  blocks,  in- 
vented toward  the  end  of  the  thirteenth  century  by  a  twin 
brother  and  sister  of  the  illustrious  family  of  Cunio,  lords  of 
Italy :  these  consisted  of  nine  engravings  of  the  "  Heroic 
Actions  "  of  Alexander  the  Great,  and,  as  stated  in  the  title- 
page,  "  first  reduced,  imagined,  and  attempted  to  be  executed 
in  relief,  with  a  small  knife,  on  blocks  of  wood  " ;  "  all  this  was 
done  and  finished  by  us  when  only  sixteen  years  of  age."  This 
title,  if  genuine,  presents  us  at  once  with  the  origin,  execution, 
and  design  of  the  first  attempts  at  block  printing.  The  next 
earliest  evidence  is  a  decree  found  among  the  archives  of  the 
Company  of  Printers  at  Venice,  dated  1441,  relating  to  playing 
cards,  printed  from  wood  blocks,  the  impressions  being  taken 
by  means  of  a  burnisher.  Then,  instead  of  a  single  block  a 
series  of  blocks  was  employed,  in  engravings  of  the  Biblia 
Pauperum,  the  text  being  printed  from  movable  types. 

We  have  now  reached  the  practice  of  printing,  in  the  pres- 
ent sense  of  the  term.  The  invention  of  the  movable  types  is 
disputed  by  many  cities,  but  only  three  have  the  slightest  claim 
—Haarlem,  Strasburg,  and  Mentz:  Haarlem  for  Lawrence 
Koster,  who,  when  "  walking  in  a  suburban  grove,  began  first 
to  fashion  beech  bark  into  letters,  which  being  impressed 
upon  paper,  reversed  in  the  manner  of  a  seal,  produced  one 
verse,  then  another,  as  his  fancy  pleased,  to  be  for  copies 
for  the  children  of  his  son-in-law."  Next,  he,  with  his  son- 
in-law,  devised  "a  more  glutinous  and  tenacious  species  of 
writing  ink,  which  he  had  commonly  used  to  draw  letters; 
thence  he  expressed  entire  figured  pictures,  with  characters 
6 


82  ACHIEVEMENTS  IN  SCIENCE 

added,"  only  on  opposite  pages,  not  printed  on  both  sides. 
Afterward  he  changed  beech  blocks  for  lead,  and  then  for  tin. 
The  tradition  adds  that  an  unfaithful  servant,  having  fled  with 
the  secret,  set  up  for  himself  at  Strasburg  or  Mentz ;  but  the 
whole  story,  which  claims  the  substitution  of  movable  for  fixed 
letters  as  early  as  1430,  cannot  be  traced  beyond  the  middle 
of  the  sixteenth  century,  and  is  generally  discredited  as  a  ro- 
mantic fiction.  Nevertheless  some  have  believed  that  a  book 
called  Speculum  Humance  Salvationis,  of  very  rude  wooden 
characters,  proceeded  from  the  Haarlem  press  before  any  other 
that  is  generally  recognized.  Whether  movable  wooden  char- 
acters were  ever  employed  in  any  entire  work  is  very  question- 
able ;  they  appear,  however,  in  the  capital  letters  of  some  early 
printed  books.  "But,"  says  Hallam,  "no  expedient  of  this 
kind  could  have  fulfilled  the  great  purposes  of  this  invention, 
until  it  was  perfected  by  founding  metal  types  in  a  matrix  or 
mould ;  the  essential  characteristic  of  printing,  as  distinguished 
from  other  arts  that  bear  some  analogy  to  it." 

The  invention  is  now  unhesitatingly  ascribed  to  John  Guten- 
berg, a  native  of  Mentz ;  the  evidence  of  which  does  not  rest 
upon  guesses  from  dateless  woodcuts,  but  upon  a  legal  docu- 
ment, dated  1439,  by  which  it  is  proved  that  Gutenberg,  being 
engaged  "  in  a  wonderful  and  unknown  art,"  admitted  certain 
persons  into  partnership,  one  of  whom  dying,  his  brother 
claimed  to  be  admitted  as  his  successor;  and  on  Gutenberg's 
refusal,  they  brought  an  action  against  him  as  principal  partner. 
From  the  evidence  produced  in  the  trial,  it  was  proved  that 
one  of  the  witnesses  had  been  instructed  by  Gutenberg  to 
"  take  the  stucke  (pages)  from  the  presses,  and,  by  removing 
two  screws,  thoroughly  separate  them  from  one  another,  so 
that  no  man  may  know  what  it  is."  From  this  curious  docu- 
ment (says  the  latest  investigator  of  the  subject)  may  be  learnt 
that  separate  types  were  used ;  for  if  they  were  block,  arranged 
so  as  to  print  four  pages  (as  stated  in  the  evidence),  how  could 
they  be  so  pulled  to  pieces  that  no  one  should  know  what  they 
were,  or  how  could  the  abstraction  of  two  screws  cause  them 
to  fall  to  pieces  ?  We  are  here  reminded  that  within  compara- 
tively few  years  screws  have  been  substituted  for  quoins,  or 


LABOR-SAVING  MACHINERY  83 

wedges,  in  locking  up  the  type  in  the  chases,  or  iron  frames ; 
which  may  be  a  revival  of  Gutenberg's  screw  method  of  four 
hundred  years  since. 

It  seems  that  some  sort  of  presses  were  now  used,  and  the 
transfers  no  longer  taken  by  a  burnisher  or  roller ;  and  lastly, 
that  the  art  was  still  a  great  secret  at  the  time  when  Koster 
was  at  the  point  of  death.  Hence  it  is  manifest  that  the  inge- 
nuity of  Gutenberg  had  made  a  vast  advance  from  the  rude 
methods  of  the  time,  and  had  in  fact  invented  a  new  and  hitherto 
unknown  art. 

All  this  took  place  at  Strasburg,  where  Gutenberg  resided 
many  years ;  but  it  did  not  lead  to  any  practical  result,  and  the 
first  book  was  printed  at  Mentz,  near  which  the  inventor  was 
born.  Thither  Gutenberg  returned  about  the  year  1450,  with 
all  his  materials.  His  former  partnership  had  expired,  and  at 
Mentz  he  associated  himself  with  John  Fust,  a  wealthy  gold- 
smith and  citizen,  who,  upon  agreement  of  being  taught  the 
secrets  of  the  art,  and  admitted  into  the  participation  of  the 
profits,  advanced  the  necessary  funds,  2,020  florins.  The  new 
partnership  then  hired  a  house  called  Zum  Jungen,  and  took 
into  their  employ  Peter  Schceffer  and  others.  A  law  suit  arose 
between  the  partners  in  1455;  and  from  a  document  in  exist- 
ence we  learn  that,  having  expended  the  whole  of  his  consider- 
able private  fortune  in  his  experiments,  Gutenberg  had  mort- 
gaged his  printing  materials  to  Fust,  which  is  proved  by  the 
initial  letters  used  by  Gutenberg  and  his  partners  in  printing 
works  between  1450  and  1455,  being  likewise  used  by  Fust  and 
Schceffer  in  the  Psalter  of  1457  and  1459.  Gutenberg  did  not, 
however,  abandon  the  unprofitable  pursuit,  but  starting  anew 
at  Mentz,  carried  on  the  business  for  ten  years;  but  in  1465, 
on  becoming  one  of  the  band  of  gentleman  pensioners  of  the 
Elector  Adolphus  of  Nassau,  "  he  finally  abandoned  the  pursuit 
of  an  art,  which,  though  it  caused  him  infinite  trouble  and  vexa- 
tion, has  been  more  effectual  in  preserving  his  name  and  the 
memory  of  his  acts  than  all  the  warlike  deeds  and  great  achieve- 
tments  of  his  renowned  master  and  all  his  house"  (Hansard) 
Gutenberg  died  on  the  24th  day  of  February,  1468.  His  print- 
ing office  and  materials  were  eventually  sold  to  Nicholas 


84  ACHIEVEMENTS  IN  SCIENCE 

Bechtermunze  of  Elfield,  whose  works  are  greatly  sought  after 
by  the  curious,  as  they  afford  much  proof,  by  collation,  of  the 
genuineness  of  the  works  attributed  to  his  great  predecessor. 

It  is  hard  to  apportion  the  share  of  honor  to  which  each  of 
the  partners — Gutenberg,  Fust,  and  Schceffer — is  entitled  in 
advancing  their  art.  Gutenberg  would  readily  suggest  a  new 
and  expeditious  method  of  manufacturing  types ;  the  practical 
skill  of  Fust  as  a  worker  in  metals,  and  his  large  pecuniary  re- 
sources, would  provide  the  necessary  appliances ;  and  the  entire 
conception  and  execution  of  the  casting  of  type  is  given  to 
Schceffer.  The  only  evidence  shows  that  the  partners  had  for 
some  time  taken  casts  of  types  in  molds  of  plaster;  for  the 
types  of  Gutenberg's  earlier  efforts,  both  at  Strasburg  and  at 
Mentz,  were  cut  out  of  single  pieces  of  wood  or  metal  with  in- 
finite labor  and  imperfection.  Schceffer  has  therefore  an  un- 
doubted claim  to  be  considered  as  one  of  the  three  inventors  of 
printing;  for  it  was  he  who  first  suggested  the  cutting  of 
punches,  whereby  beautiful  forms  could  be  stamped  upon  the 
matrix,  and  the  highest  sharpness  and  finish  given  to  the  face. 
Lambinet,  who  thinks  "  the  essence  of  the  art  of  printing  is  in 
the  engraved  punch,"  naturally  gives  the  chief  credit  to 
Schceffer ;  this  is  not  the  generally  received  opinion ;  but  he  is 
entitled  to  a  place  on  the  right  hand  of  Gutenberg.  It  should 
be  noted,  that  there  is  no  book  known  which  bears  the  conjoint 
names  of  Gutenberg,  Fust,  and  Schceffer,  nor  any  which  has 
the  imprint  of  Gutenberg  alone ;  but  there  are  several  books 
which,  from  internal  evidence,  are  unanimously  attributed  by 
the  literati  of  all  parties  and  opinions  to  Gutenberg's  press. 

It  is  curious  to  observe  that  war  was  the  means  of  quicken- 
ing the  growth  and  extension  of  printing.  In  1462,  the  storm- 
ing of  Mentz  dispersed  the  workmen,  and  gave  the  secret  to 
the  world.  In  1465,  it  appeared  in  Italy;  in  1469,  in  France; 
in  1474,  Caxton  brought  it  to  England;  and  in  1477,  it  was 
introduced  into  Spain. 

It  is  generally  believed  that  William  Caxton  was  born  in 
the  Weald  of  Kent.  About  1412  he  was  put  apprentice  to  a 
mercer  or  merchant  of  London,  became  a  traveling  agent  or 
factor  in  the  Low  Countries,  and  there  bought  manuscripts 


LABOR-SAVING  MACHINERY  85 

and  books,  with  other  merchandise.  He  there  also  learned  the 
new  art  of  printing;  and,  securing  one  of  Fust  and  Schceffer's 
fugitive  workmen  from  Mentz,  he  established  a  printing  office 
at  Cologne,  and  there  printed  the  French  original  and  his  owrr 
translation  of  the  Recuyell  of  the  History es  of  Troy.  He  after- 
ward transferred  his  materials  to  England,  and  brought  over 
with  him  Wynkyn  de  Worde,  who  probably  was  the  first  super- 
intendent of  Caxton's  printing  establishment.  He  set  up  his 
first  press  at  Westminster,  perhaps  in  one  of  the  chapels  at- 
tached to  the  Abbey,  and  certainly  under  the  protection  of  the 
abbot ;  and  he  there  produced  the  first  book  printed  in  Eng- 
land, The  Game  of  Chesse,  completed  on  the  last  day  of  March, 
1474.  His  "  capital  work  "  was  a  Book  of  the  Noble  Historyes 
of  Kyng  Arthur,  the  most  beautiful  production  of  his  press. 
He  died  in  1491,  being  about  fourscore  years  of  age.  His  in- 
dustry and  devotedness  are  recorded  in  the  fact  that  he  finished 
his  translation  of  the  Vita  Patrum,  from  French  into  English, 
on  the  last  day  of  his  life. 

Caxton  was  buried  in  the  old  church  of  St.  Margaret,  built 
in  the  reign  of  Edward  I.,  and  of  which  few  traces  remain. 
The  parish  books  contain  an  entry  of  the  expense  "for  iiij 
torches  "  and  "  the  belle  "  at  the  old  printer's  "  bureying  " ;  and 
the  same  books  record  the  churchwardens'  selling  for  6^.  8d. 
one  of  the  books  bequeathed  to  the  church  by  Caxton !  In  the 
chancel  a  tablet  to  his  memory  was  raised  in  1820  by  the  Rox- 
burghe  Club. 

A  few  words  about  the  first  presses.  Gutenberg  is  thought 
to  have  felt  the  want  of  a  machine  of  sufficient  power  to  take 
the  impressions  of  the  types  or  blocks  which  he  employed ;  nor 
is  it  supposed  that,  with  cutting  type,  forming  screws,  making 
and  inventing  ink,  he  could  have  had  time  to  construct  a  press, 
even  had  he  possessed  the  requisite  mechanical  skill.  His 
junction  with  Fust  and  Schoeffer  is  thought  to  have  supplied 
the  defect. 

The  earliest  form  of  printing  press  very  closely  resembled 
the  common  screw  press,  as  the  cheese  or  napkin  press,  with 
some  contrivance  for  running  the  form  of  types,  when  inked 
under  the  pressure  (obtained  from  the  screw  by  means  of  a 


86  ACHIEVEMENTS  IN  SCIENCE 

lever  inserted  into  the  spindle),  and  back  again  when  the  pres- 
sure is  made.  The  presses  used  in  the  office  of  Fust  and 
Schceffer  are  believed  to  have  differed  in  no  essential  form  from 
the  above,  until  improved  in  the  details  by  Blew,  a  printer  of 
Amsterdam,  in  1620.  Other  improvements  were  from  time  to 
time  introduced ;  but  they  were  all  superseded  about  the  com- 
mencement of  the  present  century,  when  the  old  wooden  press 
gave  way  to  Earl  Stanhope's  invention  of  the  iron  press  which 
bears  his  name.  Its  novelty  consisted  in  an  improved  applica- 
tion of  the  power  to  the  spindle  and  screw,  whereby  it  was 
greatly  increased.  Lord  Stanhope  also  made  some  improve- 
ments in  the  process  of  stereotyping,  and  in  the  construction 
of  locks  for  canals ;  he  invented  an  ingenious  machine  for  per- 
forming arithmetical  operations ;  during  a  great  part  of  his  life 
he  studied  the  action  of  the  electric  fluid;  and  in  1779  he 
made  public  his  theory  of  what  is  called  "  the  returning  stroke 
of  lightning."  Lord  Stanhope  bequeathed  ^"500  to  the  Royal 
Society,  of  which  he  had  been  a  fellow  fifty-one  years. 

The  principle  of  the  Stanhope  press  has  been  followed  out 
by  several  subsequent  inventors ;  and  improvements  of  mechani- 
cal detail  introduced,  tending  to  the  economy  of  time  and  labor, 
and  to  precision  of  workmanship.  The  printing  press,  how- 
ever, proved  inadequate  to  a  rate  of  production  equal  to  the  de- 
mand ;  and  as  early  as  1 790,  even  before  the  Stanhope  press 
was  generally  known,  Mr.  W.  Nicholson  patented  a  printing 
machine,  of  which  the  chief  points  were  the  following:  "The 
type,  being  rubbed  or  scraped  narrower  towards  the  bottom, 
was  to  be  fixed  upon  a  cylinder,  in  order,  as  it  were,  to  radiate 
from  the  centre  of  it.  This  cylinder,  with  its  type,,  was  to  re- 
volve in  gear  with  another  cylinder  covered  with  soft  leather 
(the  impression  cylinder),  and  the  type  received  its  ink  from 
another  cylinder,  to  which  the  inking  apparatus  was  applied. 
The  paper  was  impressed  by  passing  between  the  type  and 
impression  cylinders"  (Hansard).  Such  was  the  first  print- 
ing machine ;  it  was  never  brought  into  use,  although  most  of 
Nicholson's  plans  were,  when  modified,  adopted  by  after-con- 
structors. 

Konig,  a  German,  conceived  nearly  the  same  idea;   and 


LABOR-SAVING  MACHINERY  87 

meeting  with  the  encouragement  in  England  which  he  failed 
to  receive  on  the  Continent,  constructed  a  printing  machine 
for  Mr.  Walter;  and  on  November  28,  1814,  the  readers 
of  the  "  Times  "  were  informed  that  they  were  then,  for  the 
first  time,  reading  a  newspaper  printed  by  machinery  driven  by 
steam  power,  and  working  at  the  rate  of  1,100  impressions  per 
hour.  In  this  machine  the  ordinary  type  was  used,  and  laid 
upon  a  flat  surface,  the  impression  being  given  by  the  form 
passing  under  a  cylinder  of  great  size. 

The  later  improvements  in  printing  cannot  be  adequately 
described  in  brief.  Every  one  knows  something  of  the  wonder- 
ful typesetting  machines  by  which  one  operator,  sitting  before 
what  looks  like  an  enlarged  typewriter,  does  the  labor  of  five 
hand  compositors.  By  tapping  the  keys  he  causes  molten 
metal  to  come  out  in  the  form  of  a  line  of  solid  type,  ready  to  be 
inked  and  printed  from.  Hence  the  name  Linotype.  One  of 
the  most  recent  developments  of  this  principle  is  the  Lanston 
Monotype  machine,  which  is  at  work  producing  magazines  and 
books.  The  inventor  describes  it  thus : 

"  A  perfect  typesetting  machine  should  take  the  place  of 
the  hand  compositor,  setting  the  type  letter  by  letter  in  proper 
order  at  a  maximum  speed  and  with  a  minimum  chance  of  error. 
The  Lanston  Monotype  machine  solves  this  problem  marvel- 
ously.  To  one  who  has  seen  the  slow  work  of  hand  typeset- 
ting as  the  compositor  builds  up  a  long  column  of  metal  piece 
by  piece,  letter  by  letter,  picking  up  each  character  from  its 
allotted  space  in  the  font,  and  placing  it  in  its  proper  order  and 
position,  and  then  realizes  that  much  of  the  printed  matter  he 
sees  is  so  produced,  the  wonder  is  how  anything  is  ever  accom- 
plished. 

In  a  quarto  page  of  good-sized  type  there  are  about  7,000 
separate  pieces  (not  including  spaces)  of  type,  which,  if  set  by 
hand,  would  have  to  be  taken  one  by  one  and  placed  in  the 
compositor's  "stick,"  then  when  the  line  is  nearly  set  it  would 
have  to  be  spaced  out  or  justified  to  fill  out  the  line  exactly. 
Then  when  the  compositor's  "  stick  "  is  full,  or  two  and  a  half 
inches  have  been  set,  the  type  has  to  be  taken  out  and  placed 
in  a  long  channel  or  "  galley."  Each  of  these  three  operations 


88  ACHIEVEMENTS  IN  SCIENCE 

requires  considerable  time  and  close  application,  and  with  each 
change  there  is  the  possibility  of  error.  It  is  a  long,  expensive 
process — a  process  in  which  the  human  equation  is  far  too 
prominent.  These  three  steps  of  hand  composition,  slow,  ex- 
pensive, open  to  many  chances  of  mistake,  have  been  covered 
at  one  stride  at  five  times  the  speed,  at  one-third  the  cost,  and 
much  more  accurately  by  the  Monotype  Machine. 

A  man  sits  at  a  keyboard,  much  like  a  typewriter  in  appear- 
ance, containing  every  character  in  common  use  (two  hundred 
and  twenty-five  in  all),  and  at  a  speed  only  limited  by  his  dex- 
terity he  plays  on  the  keys  exactly  as  a  typewriter  works  his 
machine.  This  is  the  sum  total  of  human  effort  expended. 
The  machine  does  all  the  rest  of  the  work ;  furnishes  the  brains, 
and  delivers  the  product  in  clean,  shining  new  type,  each  piece 
perfect,  each  in  its  place,  each  line  of  exactly  the  right  length, 
and  each  space  between  the  words  mathematically  equal — ab- 
solutely "justified."  It  is  practically  hand  composition  with 
the  human  possibility  of  error,  of  weariness,  of  inattention,  of 
ignorance,  eliminated,  all  accomplished  with  a  celerity  that  is 
astonishing. 

The  Lanston  is  a  typecasting  machine  as  well  as  typesetter. 
It  casts  the  type  (individual  characters)  it  sets,  perfect  in  face 
and  body,  capable  of  being  used  in  hand  composition  or  put  to 
press  directly  from  the  machine  and  printed  from.  As  each 
piece  of  type  is  separate,  alterations  are  easily  made — the  cor- 
rected type,  which  the  machine  itself  casts,  is  simply  substituted 
for  the  defective  matter,  as  in  hand  composition. 

The  machine  is  composed  of  two  parts,  the  keyboard  and 
the  casting-setting  machine.  The  keyboard  part  may  be  placed 
wherever  convenient,  away  from  noise  or  anything  that  is  likely 
to  distract  or  interrupt  the  operator,  and  the  perforated  roll  of 
paper  produced  by  it  (which  governs  the  setting  machine)  may 
be  taken  away  as  fast  as  it  is  finished.  In  the  casting-setting 
machine  is  located  the  brains.  The  five-inch  roll  of  paper  per- 
forated by  the  keyboard  machine  (a  hole  for  every  letter)  gives 
the  signal  by  means  of  compressed  air  to  the  mechanism  that 
puts  the  matrix  (or  type  mould)  in  position  and  casts  the  type 
letter  by  letter,  each  character  following  the  proper  sequence 


LABOR-SAVING  MACHINERY  89 

as  marked  by  the  perforations  of  the  paper  ribbon.  By  means 
of  an  indicator  scale  on  the  keyboard  the  operator  is  informed 
how  many  spaces  there  are  between  the  words  of  the  line  and 
the  remaining  space  to  be  filled  out  to  make  the  line  the  proper 
width.  This  information  is  marked  on  the  paper  ribbon  by  the 
pressure  of  two  keys,  and  when  the  ribbon  is  transferred  to  the 
casting  machine  these  space  perforations  so  govern  the  casting 
that  the  line  of  type  delivered  at  the  "  galley  "  complete  shall  be 
exactly  the  proper  length  and  the  spaces  between  the  words  be 
equal  to  the  infinitesimal  fraction  of  an  inch. 


LABOR-SAVING  MACHINERY 


Shoemaking  Machines 

By  EARL  MAYO 

THE  commonest  things  are  the  greatest  mysteries.  We 
search  for  the  unknown  and  surprising  to  the  uttermost 
parts  of  the  earth,  when,  if  we  were  wise  enough  to  look  there, 
we  might  find  both  under  our  very  noses,  or  under  our  very 
feet. 

To  make  good  this  statement  in  its  most  literal  sense,  take 
the  shoe  as  an  example.  Certainly  nothing  is  more  common, 
more  familiar,  or  more  ubiquitous  than  the  shoe.  To  provide  the 
American  people  with  footwear  requires  close  to  half  a  million 
pairs  per  day.  There  is  no  object  more  familiar  to  us  all  than 
a  shoe,  and  yet  of  the  mystery  of  its  creation,  of  the  marvelous 
ingenuity  applied  in  its  construction,  not  one  man  out  of  a  hun- 
dred picked  at  random  from  the  street  could  tell  anything. 

But  there  is  no  mystery  about  the  making  of  a  shoe,  you 
say ;  and  if  pressed  to  the  point,  you  may  succeed  in  describing 
with  fair  exactitude  the  tedious  operations  of  the  leathern- 
aproned  cobbler  whom  you  used  to  pass  each  morning  on  your 
way  to  school,  slowly  pounding  the  leather  to  the  shape  of  his 
last,  punching  with  his  awl,  drawing  his  waxed  ends  through 
and  through  the  leather,  trimming  with  his  queer-shaped  knives. 
You  have  an  idea  that  the  methods  of  the  old  cobbler  have 
been  improved  upon  somewhat,  but  you  do  not  realize  that, 
measured  by  the  march  of  industrial  progress,  he  is  as  distant 
as  the  middle  ages.  It  took  the  cobbler  three  days  to  make  a 
pair  of  shoes.  I  have  just  visited  a  factory  in  Boston  where 
8.000  pairs  of  shoes  are  turned  out  every  day  by  a  force  of 

90 


LABOR-SAVING  MACHINERY  91 

2,400  operators.  This  means  three  and  one-half  pairs  for  every 
man,  woman,  and  child  employed  in  the  place.  And  yet  not 
one  of  them  possesses  the  skill  of  the  vanished  cobbler ;  not 
one  of  them  could  make  a  pair  of  shoes  unaided  by  his  fellows, 
and  not  more  than  two-thirds  of  them  are  employed  directly  in 
making  shoes.  The  difference  in  the  rate  of  production  be- 
tween the  new  workman  and  the  old  represents  the  share  that 
machinery  has  come  to  play  in  the  sphere  of  production.  The 
results  of  the  cobbler's  experienced  efforts  have  been  multi- 
plied by  fifteen,  and  the  multiplier  is  the  complex  machinery 
that  inventive  genius  has  supplied  to  do  the  work  of  human 
hands  and  brains — machines  that  almost  think. 

While  these  machines  have  increased  enormously  the  possi- 
bilities of  production,  they  have  also  complicated  the  methods 
by  which  these  results  are  attained.  It  doubtless  will  surprise 
the  average  reader  to  be  told  that  the  shoes  on  his  feet  have 
passed  through  fully  a  hundred  operations  in  their  progress 
from  the  sheet  of  leather  to  the  finished  product;  that  there 
are  fully  this  number  of  separate  parts  in  every  pair  of  shoes, 
and  that  some  seventy  or  eighty  hands  have  helped  to  shape 
them  into  what  they  are.  But  if  he  could  view  the  transforma- 
tion as  it  takes  place  thousands  of  times  each  day  beneath  the 
roof  of  every  great  shoe  manufactory,  if  he  could  watch  the 
leather  assuming  useful  form  as  one  intelligent  piece  of  mech- 
anism after  another  contributes  its  part  toward  the  common 
result,  he  would  be  more  astonished  than  he  can  be  by  any 
mere  description. 

To  make  thousands  of  highly  specialized  workmen  and 
thousands  of  highly  specialized  machines  work  together  in  an 
economical,  orderly,  and  profitable  manner  requires  a  thorough 
systematization.  Thus  every  great  shoe  manufactory  is  so 
arranged  that  the  raw  material,  starting  at  one  end  of  the  fac- 
tory beneath  the  roof  as  a  sheet  of  leather,  emerges  on  the 
ground  floor  as  a  completed  shoe  ready  to  wear.  To  view  the 
evolution  of  the  shoe,  therefore,  let  us  mount  together  to  the 
top  of  a  big  factory  devoted  to  turning  out  a  medium  grade  of 
shoes — shoes  that  can  be  purchased  for  three  dollars  or  three 
dollars  and  a  half  per  pair. 


92  ACHIEVEMENTS  IN  SCIENCE 

At  the  outset  we  encounter  a  mechanical  wonder,  a  machine 
that  knows  arithmetic  far  better  than  we  do,  and  that  can  per- 
form instantaneously  and  easily  a  task  that  even  a  highly  intel- 
ligent man  could  execute  only  slowly  and  tediously. 

The  leather  comes  into  the  factory  in  the  form  of  pelts 
already  tanned  and  prepared.  These  skins  retain  the  same 
shape  as  when  stripped  from  the  calf  or  kid  that  they  originally 
covered.  Consequently  they  are  irregular  in  form,  having  pro- 
jections at  the  corners  representing  the  part  of  the  hide  that 
came  off  the  animal's  legs.  This  leather  is  purchased  by  the 
square  foot,  and  each  pelt  bears  a  mark  indicating  the  number 
of  square  feet  it  contains.  To  measure  each  skin  by  the  ordi- 
nary methods  would  be  an  impossible  task,  and  yet,  in  a  factory 
where  thousands  of  them  are  used  daily,  it  is  in  the  highest 
degree  important  for  the  manufacturer  to  know  whether  or  not 
he  is  receiving  full  measure. 

To  meet  this  requirement  a  very  skillful  machine  has  been 
devised.  It  is  a  primitive  affair  in  appearance,  consisting  of  a 
broad  table,  close  to  the  surface  of  which  are  set  a  number  of 
wheels  placed  close  together  on  a  horizontal  axle  on  which  they 
can  revolve  freely.  Above  the  wheels,  attached  to  the  frame- 
work of  the  machine,  are  a  series  of  balances  arranged  exactly 
as  in  an  old-fashioned  pair  of  scales,  and  surmounting  the  whole 
thing  is  a  dial  carrying  an  indicator  marked  off  by  figures,  with 
spaces  to  show  halves  and  quarters.  Some  odd-fangled  weigh- 
ing machine,  one  would  say  at  first  glance,  but  it  is  in  reality  a 
measuring  machine  instead. 

Forming  a  part  of  each  wheel  and  projecting  from  its  side 
is  a  raised  portion  forming  a  segment  of  the  circle  represented 
by  the  wheel  itself.  Attached  to  one  end  of  the  arc  of  each 
segment  is  a  wire  chain  extending  over  the  pulleys  carried  on 
the  arms  of  the  balance.  If  the  wheels  are  set  in  motion, 
their  movement  pulls  downward  on  the  chains,  which  in  turn 
exert  a  pull  on  the  arms  of  the  balance ;  and  the  latter,  being 
connected  with  the  indicator  of  the  dial,  deflect  it. 

The  space  between  the  table  and  the  set  of  wheels  is  just 
about  wide  enough  for  a  sheet  of  paper  to  pass  through.  Set 
in  the  table  to  come  exactly  flush  with  its  surface  is  a  pair  of 


LABOR-SAVING  MACHINERY  93 

rolls  which  are  set  in  motion  whenever  the  machine  is  con- 
nected with  the  driving  shaft  that  runs  all  the  machinery  in 
the  room.  If  a  pelt  is  placed  on  the  table,  these  rolls  carry  it 
forward ;  it  comes  in  contact  with  some  of  the  set  of  wheels ; 
the  wheels  turn,  and  their  pull  moves  the  indicator  forward 
across  the  face  of  the  dial. 

Now  the  beauty  of  this  mechanism  is  that  its  pulleys  are  so 
adjusted,  in  accordance  with  laws  which  every  schoolboy  learns 
in  his  study  of  physics,  that  the  deflection  of  the  indicator 
marks  on  the  dial  exactly  the  number  of  square  feet  in  the  sur- 
face of  the  side  of  leather  that  passes  beneath  the  wheels.  It 
matters  not  what  the  shape  of  the  pelt  may  be,  square,  circular, 
or  irregular,  each  part  of  it  passes  under  some  of  the  wheels  on 
the  axle,  and  causes  them  to  move  while  it  is  passing  beneath 
them  and  only  them.  Only  a  few  seconds  are  required  in  the 
process,  and  the  area  of  the  leather  is  measured  exactly  to  the 
fraction  of  a  foot.  Of  course  not  all  the  pelts  that  come  into 
the  factory  are  measured;  from  each  case  that  is  opened 
a  few  are  tested  merely  to  verify  the  figures  of  the  seller. 
If  any  discrepancy  is  found,  the  deficient  pelts  are  not  ac- 
cepted. 

The  first  step  in  the  actual  construction  of  the  shoe  is  the 
cutting  out  of  the  leather  and  linings  by  patterns.  There  are 
separate  patterns  for  each  part,  for  each  width  and  size,  for 
each  style ;  separate  patterns  for  right  and  left  shoes.  A  great 
amount  of  skill  and  art  goes  into  the  making  of  these  patterns, 
and  of  the  lasts  on  which  the  embryo  shoes  are  placed  later  on 
in  their  careers.  The  chief  pattern  maker  of  a  big  concern 
frequently  receives  a  salary  of  $5,000  or  thereabouts.  Many 
of  the  manufacturers  buy  their  patterns  and  lasts  ready  made, 
and  the  manufacture  of  these  is  really  a  separate  branch  of  the 
business. 

In  the  cutting  department  we  again  confront  the  work  of 
labor-saving  machinery.  A  machine  with  a  heavy  beam,  work- 
ing exactly  like  a  pile-driver,  is  cutting  out  linings,  sending  the 
sharp-edged  steel  form  through  thirty-two  thicknesses  of  cloth 
at  each  blow.  Rather  more  rapid  that  than  cutting  out  each 
lining  with  a  pair  of  shears,  is  it  not  ?  But  the  machine  is  of 


94  ACHIEVEMENTS  IN  SCIENCE 

the  powerful,  lumbering  sort  that  lacks  intelligence,  and  does 
not  interest  us  particularly. 

One  point  we  need  to  observe  here  in  the  cutting-room  in 
order  to  understand  how  it  is  that  dozens  of  different  parts 
entering  into  the  construction  of  the  shoe  are  kept  from  becom- 
ing hopelessly  scattered.  Attached  to  each  bundle  of  parts  as 
it  is  cut  out  is  a  long  sheet  covered  with  letters  and  figures 
which  form  the  specifications  for  each  pair  of  shoes,  or  rather 
for  the  number  of  pairs  that  are  to  be  made  from  the  one 
model  at  one  time.  The  sheet  is  perforated  so  that  it  may  be 
divided  into  three  or  four  sections,  but  each  section  contains 
the  same  stamped  number.  Some  part  of  this  tag  is  attached 
to  each  of  the  parts  of  the  shoe,  so  that,  however  widely  sepa- 
rated the  parts  may  become  in  their  progress  through  the  fac- 
tory, they  are  brought  together  again  at  the  proper  time  and 
place.  The  specification  sheet  serves  another  useful  purpose. 
As  each  sheet  contains  a  separate  number,  which  is  also  stamped 
on  the  inside  of  the  shoe,  it  is  possible,  by  referring  to  this 
number,  to  trace  the  history  of  every  pair  of  shoes  back,  even 
to  the  cutting-room,  and  through  the  hands  of  every  operator 
who  had  a  part  in  its  production. 

The  processes  of  sewing  together  the  different  parts  form- 
ing the  upper  and  lining  of  the  shoe  and  the  making  of  button- 
holes call  for  no  particular  description.  They  go  on  in  what 
are  known  as  the  stitching-rooms,  where  hundreds  of  women, 
ranged  before  hundreds  of  sewing  machines,  are  busily  at  work. 
Some  of  these  machines  present  variations  on  familiar  models, 
and  perform  tasks  that  are  beyond  the  range  of  ordinary  sew- 
ing machines. 

By  far  the  cleverest  piece  of  mechanism  in  this  department 
is  the  apparatus  for  stamping  holes  and  putting  in  the  eyelets 
through  which  the  laces  are  to  run.  This  machine  has  an  arm 
extending  out  like  the  arm  of  a  sewing  machine.  Along  this 
arm  is  a  grooved  passage  way  leading  from  a  hopper  above  the 
machine  The  hopper  is  filled  with  blank  forms  of  eyelets 
which  are  swept  into  the  groove  by  a  revolving  brush.  The 
perpendicular  part  of  the  machine's  long  arm  is  governed  in  its 
motion  by  a  drive-wheel,  and  works  like  the  needle-holder  in  a 


LABOR-SAVING  MACHINERY  95 

sewing  machine,  except  that,  instead  of  a  continuous  motion,  it 
is  driven  downward  once  for  each  revolution  of  the  wheel. 

A  second  arm,  extending  alongside  and  operated  in  the 
same  way,  carries  a  punch.  When  the  shoe  is  placed  in  posi- 
tion and  the  machine  is  set  in  motion,  the  punch  is  driven 
downward,  cutting  a  circular  hole  through  the  leather.  At  the 
next  movement  the  shoe  is  carried  forward,  an  eyelet  fed  out 
of  the  groove  is  caught  by  the  point  of  the  miniature  pile-driver 
in  its  descent,  is  carried  into  the  hole  prepared  for  it,  and  neatly 
flattened  out  by  the  force  of  the  blow,  so  that  it  is  firmly  pinned 
in  position.  By  merely  pressing  a  foot  lever,  the  arm  carrying 
the  punching  apparatus  can  be  moved  forward  or  backward, 
thus  regulating  the  distance  between  the  holes. 

One  of  these  machines  will  insert  the  eyelets  in  a  case  of 
shoes  containing  thirty-six  pairs  in  fifteen  minutes.  This 
means  something  like  eighty  finished  eyelets  to  the  minute. 
The  machine  does  in  a  quarter  of  an  hour  an  amount  of  work 
that  a  skilled  artisan  could  not  accomplish  in  a  day,  and  does  it 
with  a  precision  and  regularity  that  the  human  workman 
could  not  equal.  And  the  machine  is  operated  by  a  young 
girl. 

At  this  stage  in  its  progress  the  various  pieces  forming  the 
upper  part  of  the  shoe  have  been  joined  together.  All  the 
work  has  been  done  by  machinery  except  the  cutting  out  of 
certain  parts  from  the  patterns.  Meanwhile,  in  another  part  of 
the  factory  the  materials  for  the  sole  have  been  shaping.  The 
thick  outer  covering  and  the  thin  inside  part  have  been  stamped 
out  by  forms  placed  beneath  heavy  beams  operated  as  the  one 
that  we  observed  in  the  act  of  cutting  out  the  linings.  The 
inner  sole  has  been  shaped  to  the  form  that  it  occupies  in  the 
finished  shoe  by  means  of  a  heavy  moulder  operated  by  hy- 
draulic power ;  at  the  same  time  a  ridge  has  been  raised  up 
around  the  outer  edge,  to  which  a  covering  of  canvas  is  attached 
by  a  stitching  machine,  thus  adding  greatly  to  its  holding 
power. 

The  final  step  before  the  junction  of  the  upper  shoe  and 
the  sole  is  the  sewing  on  of  the  welt,  a  strip  of  strong  leather 
which  serves  to  join  the  soft  upper  to  the  less  flexible  sole. 


96  ACHIEVEMENTS  IN  SCIENCE 

The  welt  is  attached  by  means  of  a  sewing  machine  directly 
after  the  shoe  has  gone  through  the  process  of  lasting. 

Here,  at  least,  you  will  say,  is  a  task  before  which  machinery 
is  helpless.  To  give  a  shoe  the  qualities  requisite  to  a  good  fit, 
to  keep  it  from  drawing  here  and  wrinkling  there,  it  is  neces- 
sary that  the  leather  be  drawn  carefully  over  the  wooden  last 
which  is  placed  inside  the  shoe,  and  fastened  there  with  tacks 
to  await  the  process  of  sewing.  To  become  a  competent  laster 
requires  skill  and  long  experience,  and  the  men  who  perform 
this  work  are  always  among  the  best  paid  in  the  factory.  In 
many  establishments  the  lasting  is  done  by  hand  still,  but  there 
is  a  machine  which  will  do  the  work  and  do  it  well,  and  this 
machine  is  utilized  to  a  considerable  extent  in  the  making  of 
the  cheaper  grade  of  shoes.  It  was  named  derisively  the  "  nig- 
ger "  laster  by  the  workmen,  because  of  the  fact  that  its  in- 
ventor was  a  mulatto ;  but  no  very  long  inspection  is  required 
to  convince  one  of  the  fact  that  the  machine  is  one  entitled  to 
respect. 

A  steel  thumb  and  finger,  working  on  a  steel  arm,  grip  the 
edge  of  the  leather,  and  with  the  sideways  pull  characteristic  of 
the  hand  laster  bring  the  leather  lightly  over  the  edge  of  the 
last.  At  the  end  of  the  arm's  pull,  and  just  before  the  spring 
controlling  the  thumb  and  finger  is  released,  a  second  arm  de- 
scends with  a  sharp  blow.  This  second  arm  is  an  automatic 
hammer.  Short  tacks  are  automatically  fed  along  a  narrow 
groove  from  a  small  hopper  to  a  position  directly  beneath  the 
hammer.  The  beauty  of  the  apparatus  is  that  it  drives  the  nail 
only  half  way  into  the  last,  so  that  it  may  be  pulled  out  easily 
when  the  sole  is  sewed  on ;  a  small  circular  guard  below  the 
hammer  prevents  the  nail  from  being  driven  in  for  its  full 
length.  This  mechanical  laster  works  much  more  rapidly  than 
any  hand  workman  is  capable  of  doing,  and  it  performs  a  task 
that  requires,  in  the  case  of  the  human  workman,  a  combina- 
tion of  good  judgment  with  mechanical  exactitude. 

The  lasting  is  merely  a  preparatory  step  to  the  sewing  of 
the  shoe,  which  is  done  by  another  species  of  the  remarkable 
sewing  machines  that  are  so  much  in  evidence  throughout  the 
factory.  The  entire  welt  is  sewed  on  in  a  fraction  of  a  second, 


LABOR-SAVING  MACHINERY  97 

instead  of  the  half  hour  occupied  by  the  laborious  method  of 
the  old-time  hand  operator.  A  cutting  machine,  following  the 
sewer,  neatly  trims  off  the  edges. 

The  shoe  is  now  ready  to  enter  upon  another  stage  of  its 
construction — the  affixing  of  the  outer  sole  and  heel ;  and  we 
notice  the  fact  that  up  to  this  point  the  light  shoes  for  women 
have  been  put  together  inside  out,  although  this  is  not  the  case 
with  men's  footwear. 

The  space  between  the  inner  and  outer  soles  is  filled  with  a 
substance  the  composition  of  which  varies  according  to  the 
notion  of  the  manufacturer  or  the  quality  of  the  shoe.  The 
most  common  is  a  mixture  of  ground  cork  and  cement,  which 
is  useful  in  resisting  damp,  and  at  the  same  time  assists  the 
wearing  quality  of  the  shoe.  When  this  has  been  done,  the 
shoe  is  placed  on  a  form  beneath  a  heavy  weight.  The  outer 
sole  is  covered  with  rubber  cement  laid  in  position,  and  pressed 
upon  the  shoe.  The  cement  holds  it  in  place  temporarily  until 
it  can  be  sewed  together  by  a  machine  that  drives  both  needle 
and  thread  right  through  the  heavy  sole  and  affixes  it  firmly  to 
the  welt. 

Next  comes  into  play  a  very  simple  but  extremely  ingenious 
machine.  The  shoe  is  placed  on  another  form,  and  a  heavy 
roller,  carrying  a  pressure  of  two  tons,  is  run  over  the  sole, 
forcing  it  down  compactly  upon  the  upper,  and  giving  it  the 
neatly  rounded  and  finished  appearance  which  the  bottom  of  a 
new  shoe  presents.  The  arm  carrying  this  roller  moves  back- 
ward and  forward,  and  is  so  geared  as  to  have  also  a  rocking 
motion.  Consequently  the  roller  passes  over  every  inch  of  the 
shoe's  bottom  surface,  and  its  movements  as  it  runs  forward  and 
backward,  tilting  from  side  to  side,  are  remarkably  humanlike, 
and  suggest  the  presence  of  a  brain  hidden  away  somewhere  in 
the  machine  and  directing  its  operations. 

When  the  sole  has  been  put  in  place,  the  heel  is  affixed,  and 
this  is  done  by  a  machine  suggestively  named  "  the  lightning 
nailer." 

The  various  layers  of  leather  comprising  the  heel  have  been 
pasted  together  in  another  part  of  the  factory,  or  perhaps  in 
another  factory,  for  many  of  the  shoemakers  buy  their  heels 


98  ACHIEVEMENTS  IN  SCIENCE 

ready  made.  There  remains  only  to  fasten  the  heel  to  the  shoe 
and  to  affix  the  bottom  or  outside  heel-top,  which  is  always  put 
on  separately.  To  do  this  is  the  work  of  the  lightning  nailer. 

The  machine  is  fed  from  a  hopper  into  which  the  nails  are 
poured  and  from  which  they  are  shaken  down  grooved  inclines 
to  fall  into  a  form  at  the  bottom.  The  form  is  exactly  the 
shape  of  a  shoe  heel,  and  in  it  the  nails  are  held  upright  in  the 
position  in  which  they  are  to  be  driven  into  the  shoe.  The  heel 
is  placed  in  position ;  the  arm  carrying  the  form,  filled  with  up- 
right nails,  is  carried  horizontally  about  just  above  the  heel; 
the  valve  that  has  held  the  nails  from  slipping  out  has  been 
thrown  aside  by  the  release  of  a  catch ;  a  hammer  descends  and 
drives  all  the  nails  home  at  one  blow,  and  contact  with  the  iron 
form  on  which  the  shoe  is  placed  clinches  them  on  the  inside. 
Along  comes  another  arm,  carrying  the  outside  heel-top,  over 
which  a  brushful  of  glue  has  been  passed,  and  another  smart 
blow  fastens  this  in  position,  covering  up  the  heads  of  the  nails 
which  hold  the  heel  in  place.  Another  machine,  similar  in 
operation,  drives  the  row  of  nails  which  you  may  observe  run- 
ning along  the  outer  edge  of  the  heel  of  your  shoe.  These  lat- 
ter help  hold  the  heel  together  to  some  extent,  but  they  an 
put  in  chiefly  for  appearance'  sake. 

As  soon  as  the  outer  edges  of  the  sole  and  heel  have  been 
trimmed  off  smoothly  by  swiftly  revolving  circular  knives,  the 
shoe  is  practically  complete.  It  is  cleaned  by  revolving 
brushes ;  the  sole  is  burnished  on  sandpaper  and  emery  wheels ; 
it  is  waxed  by  being  held  against  a  revolving  wax-mould ;  the 
name  and  trademark  of  the  maker  is  impressed  by  a  mechani- 
cal stamp ;  the  laces  are  inserted  by  girl  operators ;  the  shoe 
passes  through  the  hands  of  an  inspector,  and  thence  it  goes  to 
the  packing  room,  whence  it  emerges  with  thousands  of  others, 
packed  in  a  neat  cardboard  box,  ready  for  sale. 

This  rough  description  covers  only  the  essential  steps  in 
the  building  of  a  shoe  from  a  flat  strip  of  leather  into  a  form 
that  will  fit  the  human  foot.  There  are  dozens  of  minor  opera- 
tions, designed  to  add  to  the  beauty  or  finish  of  the  shoes,  that 
have  not  been  touched  upon,  and  there  are  clever  machines 
that  perform  nearly  all  these  operations. 


LABOR-SAVING  MACHINERY  99 

For  example,  if  you  look  at  the  sole  of  a  new  shoe  you 
will  notice  that  the  threads  by  which  it  is  sewn  do  not  show  at 
all.  Before  the  sole  is  sewed  to  the  welt  it  receives  the  atten- 
tion of  a  machine  carrying  a  swiftly  revolving,  sharp  little  wheel 
that  runs  around  its  edge,  turning  up  a  thin  layer  of  leather. 
After  the  sole  is  fastened  on,  this  layer  is  turned  down  and 
pressed  firmly  by  the  heavy  roller  mentioned  above.  Similarly 
there  is  the  "foxing"  machine,  which  stamps  out  the  rows  of 
holes  often  seen  along  the  edge  of  a  box-tip  or  a  vamp,  and 
which  give  the  shoe  a  finer  appearance  in  the  opinion  of  many 
buyers. 

Another  trick  of  the  clumsy  machinery  that  supplies  us 
with  footwear  imitates  the  appearance  of  a  hand-sewed  sole. 
If  you  look  on  the  top  surface  of  the  extension  sole  of  a  fash- 
ionable shoe  you  will  notice  a  series  of  little  grooves  or  cuts  ex- 
tending outward  and  separating  the  stitches  by  which  the  sole 
and  welt  are  fastened  together.  The  custom  shoemaker  cuts 
these  little  depressions  so  that  his  stitches  will  sink  in  even 
with  the  surface,  and  thus  make  his  work  less  clumsy  in  ap- 
pearance. The  machine  sewer  draws  these  stitches  as  tight  as 
it  is  possible  for  them  to  be,  but,  notwithstanding  that  they 
serve  no  practical  purpose,  the  little  grooves  are  added  to  im- 
prove the  appearance  of  the  shoe  and  to  counterfeit  the  effect 
of  hand-sewing. 

If  you  watched  the  old  cobbler  carefully  in  the  boyhood  or 
girlhood  days  in  which  your  ideas  of  shoemaking  were  formed, 
you  may  have  noticed  that  whenever  he  sewed  two  pieces  of 
leather  together,  he  was  accustomed  to  pound  down  the  seam 
with  his  hammer  to  make  it  as  flat  as  possible.  The  same 
thing  is  done  in  the  modern  factory,  except  that  the  pounding 
is  done  by  an  automatic  hammer  that  strikes  two  hundred 
blows  to  the  minute,  and  does  the  work  in  one-fiftieth  of  the 
time  required  by  the  man  of  the  awl  and  leathern  apron.  In 
fact,  inventive  genius  has  succeeded  in  turning  out  machinery 
that  performs  rapidly  and  efficiently  practically  every  operation 
that  the  most  painstaking  custom  shoemaker  of  a  generation 
ago  put  into  his  work. 


LIGHT  AND  ITS  USES 


New  Light  on   Light,  or   Revelations  of 
Spectrum   Analysis 

By  ALFRED  RUSSEL  WALLACE 

HOW  long  ago  it  is  since  the  use  of  fire,  and  some  mode  of 
producing  it,  enabled  man  to  make  the  first  advance 
toward  civilization,  we  have  no  means  of  determining.  As  a 
matter  of  fact,  the  method  of  producing  fire  by  friction  is  that 
most  common  among  savages  in  all  parts  of  the  world;  and 
since  it  requires  only  materials  that  are  almost  everywhere  at 
hand,  it  descended  even  to  some  civilized  peoples. 

The  more  convenient  method  of  striking  a  light  by  the  use 
of  flint,  steel,  and  tinder,  probably  originated  after  iron  was 
first  made,  and  soon  became  adopted  by  all  civilized  people, 
and  by  many  savages  who  possessed  iron;  and  this  method 
continued  in  use  from  the  times  of  prehistoric  man  through  all 
the  ages  of  barbarism  and  civilization  down  to  a  century  ago, 
and  the  process  underwent  hardly  any  improvement  during 
that  long  period.  One  of  the  most  vivid  recollections  of  my 
childhood  is  of  seeing  the  cook  make  tinder  in  the  evening  by 
burning  old  linen  rags,  and  in  the  morning,  with  flint  and  steel 
obtaining  the  spark  which,  by  careful  blowing,  spread  suffi- 
ciently to  ignite  the  thin  brimstone  match  from  which  a  candle 
was  lit  and  fire  secured  for  the  day.  The  process  was,  how- 
ever, sometimes,  a  tedious  one,  and  if  the  tinder  had  accident- 
ally got  damp,  or  if  the  flint  were  worn  out,  after  repeated 
failures  a  light  had  to  be  obtained  from  a  neighbor.  At  that 
time  there  were  few  savages  in  any  part  of  the  world  but  could 
obtain  fire  as  easily  as  the  most  civilized  of  mankind. 

100 


LIGHT  AND  ITS   USES  101 

At  length,  after  the  use  of  these  rude  methods  for  many 
thousand  years,  a  great  discovery  was  made  which  revolution- 
ized the  process  of  fire-getting.  The  properties  of  phosphorus 
were  known  to  the  alchemists,  and  it  is  strange  that  its  ready 
ignition  by  friction  was  not  made  use  of  to  obtain  fire  at  a 
much  earlier  period.  It  was,  however,  both  an  expensive  and 
a  dangerous  material,  and  though  about  a  hundred  years  ago  it 
began  to  be  made  cheaply  from  bones,  it  was  not  used  in  the 
earliest  friction  matches.  These  were  invented  in  1827,  or  a 
little  earlier,  by  John  Walker,  a  chemist  and  druggist  of  Stock- 
ton-on-Tees,  and  consisted  of  wood  splints,  dipped  in  chlorate 
of  potash  and  sulphur  mixed  with  gum,  which  ignited  when 
rubbed  on  sandpaper.  Two  years  later  the  late  Sir  Isaac 
Holden  invented  a  similar  match.  About  1834,  phosphorus 
began  to  be  used  with  the  other  materials  to  cause  more  easy 
ignition,  and  by  1840  these  matches  became  so  cheap  as  to 
come  into  general  use  in  place  of  the  old  flint  and  steel.  They 
have  since  spread  to  every  part  of  the  world,  and  their  produc- 
tion constitutes  one  of  the  large  manufacturing  industries  of 
England,  Sweden,  and  many  other  countries. 

Coming  now  to  the  use  of  fire  as  a  light-giver,  we  find  that 
an  even  greater  change  has  taken  place  in  our  time.  The  first 
illuminants  were  probably  torches  made  of  resinous  woods, 
which  will  give  a  flame  for  a  considerable  time.  Then  the 
resin  exuding  from  many  kinds  of  trees  would  be  collected  and 
applied  to  sticks  or  twigs,  or  to  some  fibrous  materials  tied  up 
in  bundles,  such  as  are  still  used  by  many  savage  peoples,  and 
were  used  in  the  old  baronial  halls.  For  out-door  lights  torches 
were  used  almost  down  to  our  times,  an  indication  of  which  is 
seen  in  the  iron  torch  extinguishers  at  the  doors  of  many  of 
the  older  West  End  houses;  while,  before  the  introduction  of 
gas,  link-boys  were  as  common  in  the  streets  as  match-sellers 
are  now.  Then  came  lamps,  formed  of  small  clay  cups,  holding 
some  melted  animal  fat  and  a  fibrous  wick;  and,  somewhat 
later,  rush-lights  and  candles.  Still  later,  vegetable  oils  were 
used  for  lamps  and  wax  candles ;  but  the  three  modes  of  ob- 
taining illumination  for  domestic  purposes  remained  entirely 
unchanged  in  principle,  and  very  little  improved,  throughout 


102  ACHIEVEMENTS  IN  SCIENCE 

the  whole  period  of  history  down  to  the  end  of  the  eighteenth 
century.  The  Greek  and  Roman  lamps,  though  in  beautiful 
receptacles  of  bronze  or  silver,  were  exactly  the  same  in  princi- 
ple as  those  of  the  lowest  savage,  and  hardly  better  in  light- 
giving  power ;  and  though  varipus  improvements  in  form  were 
introduced,  the  first  really  important  advance  was  made  by  the 
Argand  burner.  This  introduced  a  current  of  air  into  the  cen- 
ter of  the  flame  as  well  as  outside  it,  and,  by  means  of  a  glass 
chimney,  a  regular  supply  of  air  was  kept  up,  and  a  steady 
light  produced.  Although  the  invention  was  made  at  the  end 
of  the  last  century,  the  lamps  were  not  sufficiently  improved 
and  cheapened  to  come  into  use  till  about  1 830 ;  and  from  that 
time  onward  many  other  improvements  were  made,  chiefly  de- 
pendent on  the  use  of  the  cheap  mineral  oils,  rendering  lamps 
so  inexpensive,  and  producing  so  good  a  light,  that  they  are 
now  found  in  the  poorest  cottages. 

The  only  important  improvement  in  candles  is  due  to  the 
use  of  paraffine  fats  instead  of  tallow,  and  of  flat  plaited  wicks 
which  are  consumed  by  the  flame.  In  my  boyhood,  the  now 
extinct  "  snuffers "  were  in  universal  use,  from  the  common 
rough  iron  article  in  the  kitchen  to  elaborate  polished  steel 
spring-snuffers  of  various  makes  for  the  parlor,  with  pretty 
trays  for  them  to  stand  in.  Candles  are  still  very  largely  used, 
being  more  portable  and  safer  than  most  of  the  paraffine  oil 
lamps.  Even  our  lighthouses  used  only  candles  down  to  the 
early  part  of  the  present  century. 

A  far  more  important  and  more  radical  change  in  our  modes 
of  illumination  was  the  introduction  of  gas  lighting.  A  few 
houses  and  factories  were  lighted  with  gas  at  the  very  end  of 
the  last  century,  but  its  first  application  to  out-door  or  general 
purposes  was  in  1813,  when  Westminster  Bridge  was  illuminated 
by  it,  and  so  successfully  that  its  use  rapidly  spread  to  every 
town  in  the  kingdom,  for  lighting  private  houses  as  well  as 
streets  and  public  buildings.  When  it  was  first  proposed  to 
light  London  with  gas,  Sir  Humphrey  Davy  is  said  to  have  de- 
clared it  to  be  impracticable,  both  on  account  of  the  enormous 
size  of  the  needful  gas-holders,  and  the  great  danger  of  explo- 
sions. These  difficulties  have,  however,  been  overcome,  as 


LIGHT  AND  ITS   USES  103 

was  the  supposed  insuperable  difficulty  of  carrying  sufficient 
coal  in  the  case  of  steamships  crossing  the  Atlantic,  the  impos- 
sibilities of  one  generation  becoming  the  realities  of  the  next. 

Still  more  recent,  and  more  completely  new  in  principle,  is 
the  electric  light,  which  has  already  attained  a  considerable  ex- 
tension for  public  and  private  illumination,  while  it  is  applicable 
to  many  purposes  unattainable  by  other  kinds  of  light.  Small 
incandescent  lamps  are  now  used  for  examinations  of  the  larynx 
and  in  dentistry,  and  a  lamp  has  even  been  introduced  into  the 
stomach  by  which  the  condition  of  that  organ  can  be  examined. 
For  this  last  purpose  numerous  ingenious  arrangements  have 
to  be  made  to  prevent  possible  injury,  and  by  means  of  prisms 
at  the  bends  of  the  tube  the  operator  can  inspect  the  interior 
of  the  organ  under  a  brilliant  light.  Other  internal  organs 
have  been  explored  in  a  similar  manner,  and  many  new  appli- 
cations in  this  direction  will  no  doubt  be  made.  In  illuminat- 
ing submarine  boats  and  exploring  the  interiors  of  sunken  ves- 
sels it  does  what  could  hardly  be  effected  by  any  other  means. 

The  improvements  in  the  mode  of  production  of  light  for 
common  use  are  sufficiently  new  and  remarkable  to  distinguish 
this  century  from  all  the  ages  that  preceded  it,  but  they  sink 
into  insignificance  when  compared  with  the  discoveries  which 
have  been  made  as  to  the  nature  of  light  itself,  its  effects  on 
various  kinds  of  matter  leading  to  the  art  of  photography,  and 
the  complex  nature  of  the  solar  spectrum  leading  to  spectrum 
analysis.  This  group  of  investigations  alone  is  sufficient  to 
distinguish  the  present  century  as  an  epoch  of  the  most  mar- 
velous scientific  discovery. 

Although  Huygens  put  forward  the  wave  theory  of  light 
more  than  two  hundred  years  ago,  it  was  not  accepted,  or  seri- 
ously studied,  till  the  beginning  of  the  present  century,  when  it 
was  revived  by  Thomas  Young,  and  was  shown  by  himself,  by 
Fresnel,  and  other  mathematicians,  to  explain  all  the  phenomena 
of  refraction,  double  refraction,  polarization,  diffraction,  and  in- 
terference, some  of  which  were  inexplicable  to  the  Newtonian 
theory  of  the  emission  of  material  particles,  which  had  pre- 
viously been  almost  universally  accepted.  The  complete  estab- 
lishment of  the  undulatory  theory  of  light  is  a  fact  of  the  high- 


104  ACHIEVEMENTS  IN  SCIENCE 

est  importance,  and  will  take  a  very  high  place  among  the 
purely  scientific  discoveries  of  the  century. 

From  a  more  practical  point  of  view,  however,  nothing  can 
surpass  in  interest  and  importance  the  discovery  and  continu- 
ous improvement  of  the  photographic  art,  which  has  now 
reached  such  a  development  that  there  is  hardly  any  science  or 
any  branch  of  intellectual  study  that  is  not  indebted  to  it.  A 
brief  sketch  of  its  origin  and  progress  will  therefore  not  be  un- 
interesting. 

The  fact  that  certain  salts  of  silver  were  darkened  by  expo- 
sure to  sunlight  was  known  to  the  alchemists  in  the  sixteenth 
century,  and  this  observation  forms  the  rudiment  from  which 
the  whole  art  has  been  developed.  The  application  of  this  fact 
to  the  production  of  pictures  belongs,  however,  wholly  to  our 
own  time.  In  the  year  1802,  Wedgewood  described  a  mode  of 
copying  paintings  on  glass  by  exposure  to  light,  but  neither  he 
nor  Sir  Humphry  Davy  could  find  any  means  of  rendering 
the  copies  permanent.  This  was  first  effected  in  1814  by  M. 
Niepce  of  Chalons,  but  no  important  results  were  obtained  till 
1 839,  when  Daguerre  perfected  the  beautiful  process  known  as 
the  daguerrotype.  Permanent  portraits  were  taken  by  him  on 
silvered  plates,  and  they  were  so  delicate  and  beautiful  that 
probably  nothing  in  modern  photography  can  surpass  them. 
For  several  years  they  were  the  only  portraits  taken  by  the 
agency  of  light,  but  they  were  very  costly,  and  were  therefore 
completely  superseded  when  cheaper  methods  were  discovered. 

About  the  same  time  a  method  was  found  for  photograph- 
ing leaves,  lace,  and  other  semi-transparent  objects  on  paper, 
and  rendering  them  permanent,  but  this  was  of  comparatively 
little  value.  In  the  year  1850,  the  far  superior  collodion-film 
on  glass  was  perfected,  and  negatives  were  taken  in  a  camera- 
obscura,  which,  when  placed  on  black  velvet,  or  when  coated 
with  a  black  composition,  produced  pictures  almost  as  perfect 
and  beautiful  as  the  daguerrotype  itself,  and  at  much  less  cost. 
Soon  afterward  positives  were  printed  from  the  transparent 
negatives  on  suitably  prepared  paper,  and  thus  was  initiated 
the  process,  which,  with  endless  modifications  and  improve- 
ments, is  still  in  use.  The  main  advance  has  been  in  the  in- 


LIGHT  AND  ITS    USES  105 

creased  sensitiveness  of  the  photographic  plates,  so  that,  first, 
moving  crowds,  then  breaking  waves,  running  horses,  and  other 
quickly  moving  objects  were  taken,  while  now  a  bullet  fired 
from  a  rifle  can  be  photographed  in  the  air. 

With  such  marvelous  powers,  photography  has  come  to  the 
aid  of  the  arts  and  sciences  in  ways  which  would  have  been 
perfectly  inconceivable  to  our  most  learned  men  of  a  century 
ago.  It  furnishes  the  meteorologist,  the  physicist,  and  the  bi- 
ologist with  self-registering  instruments  of  extreme  delicacy, 
and  enables  them  to  preserve  accurate  records  of  the  most  fleet- 
ing natural  phenomena.  By  means  of  successive  photographs 
at  short  intervals  of  time,  we  are  able  to  study  the  motions  of 
the  wings  of  birds,  and  thus  learn  something  of  the  mechanism 
of  flight;  while  even  the  instantaneous  lightning-flash  can  be 
depicted,  and  we  thus  learn,  for  the  first  time,  the  exact  nature 
of  its  path. 

Perhaps  the  most  marvelous  of  all  its  achievements  is  in 
the  field  of  astronomy.  Every  increase  in  the  size  and  power 
of  the  telescope  has  revealed  to  us  ever  more  and  more  stars  in 
every  part  of  the  heavens;  but,  by  the  aid  of  photography, 
stars  are  shown  which  no  telescope  that  has  been,  or  that 
probably  ever  will  be  constructed,  can  render  visible  to  the 
human  eye.  For  by  exposing  the  photographic  plate  in  the 
focus  of  the  object  glass  for  some  hours,  almost  infinitely  faint 
stars  impress  their  image,  and  the  modern  photographic  star 
maps  show  us  a  surface  densely  packed  with  white  points  that 
seem  almost  as  countless  as  the  sands  of  the  seashore.  Yet 
every  one  of  these  points  represents  a  star  in  its  true  relative 
position  to  the  visible  stars  nearest  to  it,  and  thus  gives  at  one 
operation  an  amount  of  accurate  detail  which  could  hardly  be 
equaled  by  the  labor  of  an  astronomer  for  months  or  years — 
even  if  he  could  render  all  these  stars  visible,  which,  as  we  have 
seen,  he  cannot  do.  A  photographic  survey  of  the  heavens  is 
now  in  progress  on  one  uniform  system,  which,  when  com- 
pleted, will  form  a  standard  for  future  astronomers,  and  thus 
give  to  our  successors  some  definite  knowledge  of  the  struc- 
ture, and,  perhaps,  of  the  extent  of  the  stellar  universe. 

It  has  long  been  the  dream  of  photographers  to  discover 


106  ACHIEVEMENTS  IN  SCIENCE 

some  mode  of  obtaining  pictures  which  shall  reproduce  all  the 
colors  of  nature  without  the  intervention  of  the  artist's  manipu- 
lation. This  was  seen  to  be  exceedingly  difficult,  if  not  impos- 
sible, because  the  chemical  action  of  colored  light  has  no  power 
to  produce  pigments  of  the  same  color  as  the  light  itself,  with- 
out which  a  photograph  in  natural  colors  would  seem  to  be  im- 
possible. Nevertheless,  the  problem  has  been  solved,  but  in  a 
totally  different  manner;  that  is,  by  the  principle  of  "interfer- 
ence," instead  of  by  that  of  chemical  action. 

This  principle  was  discovered  by  Newton,  and  is  exempli- 
fied in  the  colors  of  the  soap  bubble,  and  in  those  of  mother-of- 
pearl  and  other  iridescent  objects.  It  depends  on  the  fact  that 
the  differently  colored  rays  are  of  different  wave  lengths,  and 
the  waves  reflected  from  two  surfaces  half  a  wave  length  apart 
neutralize  each  other  and  leave  the  remainder  of  the  light  col- 
ored. If,  therefore,  each  differently  colored  ray  of  light  can  be 
made  to  produce  a  corresponding  minute  wave  structure  in  a 
photographic  film,  then  each  part  of  the  film  will  reflect  only 
light  of  that  particular  wave  length,  and  therefore  of  that  par- 
ticular color  that  produced  it.  This  has  actually  been  done  by 
Professor  Lippmann,  of  Paris,  who  published  his  method  in 
1891 ;  and  in  a  lecture  before  the  Royal  Society  in  April,  1896, 
he  fully  described  it  and  exhibited  many  beautiful  specimens. 

The  principle  is  the  same  for  the  light  waves  as  that  of  the 
telephone  for  sound  waves.  The  voice  sets  up  vibrations  in  the 
transmitting  diaphragm,  which,  by  means  of  an  electric  cur- 
rent, are  so  exactly  reproduced  in  the  receiving  diaphragm  as 
to  give  out  the  same  succession  of  sounds.  An  even  more 
striking  and,  perhaps,  closer  analogy  is  that  of  the  phonograph, 
where  the  vibrations  of  the  diaphragm  are  permanently  regis- 
tered on  a  wax  clyinder,  which,  at  any  future  time,  can  be  made 
to  set  up  the  same  vibrations  of  the  air,  and  thus  reproduce  the 
same  succession  of  sounds,  whether  words  or  musical  notes. 
So,  the  rays  of  every  color  and  tint  that  fall  upon  the  plate 
throw  the  deposited  silver  within  the  film  into  minute  strata 
which  permanently  reflect  light  of  the  very  same  wave  length, 
and  therefore  of  the  very  same  color  as  that  which  produced 
them. 


LIGHT  AND  ITS   VSflS  107 

The  effects  are  said  to  be  most  beautiful,  the  only  fault 
being  that  the  colors  are  more  brilliant  than  in  nature,  just  as 
they  are  when  viewed  in  the  camera  itself.  This,  however, 
may  perhaps  be  remedied  (if  it  requires  remedying)  by  the  use 
of  a  slightly  opaque  varnish.  The  comparatively  little  atten- 
tion  that  has  been  given  to  this  beautiful  and  scientifically  per- 
fect process  is  no  doubt  due  to  the  fact  that  it  is  rather  expen- 
sive, and  that  the  pictures  cannot,  at  present,  be  multiplied 
rapidly.  But  for  that  very  reason  it  ought  to  be  especially  at- 
tractive to  amateurs,  who  would  have  the  pleasure  of  obtaining 
exquisite  pictures  which  will  not  become  commonplace  by  in- 
definite reproduction. 

The  brief  sketch  of  the  rise  and  progress  of  photography 
now  given  illustrates  the  same  fact  which  we  have  already 
dwelt  upon  in  the  case  of  other  discoveries.  This  beautiful  and 
wonderful  art,  which  already  plays  an  important  part  in  the 
daily  life  and  enjoyment  of  all  civilized  people,  and  which  has 
extended  the  bounds  of  human  knowledge  into  the  remotest 
depths  of  the  starry  universe,  is  not  an  improvement  of,  or  de- 
velopment from,  anything  that  went  before  it,  but  is  a  totally 
new  departure.  From  that  early  period  when  the  men  of  the 
stone  age  rudely  outlined  the  mammoth  and  the  reindeer  on 
stone  or  ivory,  the  only  means  of  representing  men  and  ani- 
mals, natural  scenery,  or  the  great  events  of  human  history, 
had  been  through  the  art  of  the  painter  or  the  sculptor.  It  is 
true  that  the  highest  Greek,  or  mediaeval,  or  modern  art,  can- 
not be  equaled  by  the  productions  of  the  photographic  camera ; 
but  great  artists  are  few  and  far  between,  and  the  ordinary  or 
even  the  talented  draughtsman  can  give  us  only  suggestions 
of  what  he  sees,  so  modified  by  his  peculiar  mannerism  as  often 
to  result  in  a  mere  caricature  of  the  truth.  Should  some  his- 
torian in  Japan  study  the  characteristics  of  English  ladies  at 
two  not  remote  epochs,  as  represented,  say,  by  Frith  and  by 
Du  Maurier,  he  would  be  driven  to  the  conclusion  that  there 
had  been  a  complete  change  of  type,  due  to  the  introduction  of 
some  foreign  race,  in  the  interval  between  the  works  of  these 
two  artists.  From  such  errors  as  this  we  shall  be  saved  by 
photography ;  and  our  descendants  in  the  middle  of  the  coming 


108  ACHIEVEMENTS  IN  SCIENCE 

century  will  be  able  to  see  how  much,  and  what  kind,  of  change 
really  does  occur  from  age  to  age. 

The  importance  of  this  is  well  seen  by  comparing  any  of 
the  early  works  on  ethnology,  illustrated  by  portraits  intended 
to  represent  the  different  "  types  of  mankind,"  with  recent  vol- 
umes which  give  us  copies  of  actual  photographs  of  the  same 
types ;  when  we  shall  see  how  untrue  to  nature  are  the  former, 
due  probably  to  the  artist  having  delineated  those  extreme 
forms,  either  of  ugliness  or  of  beauty,  that  most  attracted  his 
attention,  and  to  his  having  exaggerated  even  these.  Thus 
only  can  we  account  for  the  pictures  in  some  old  voyages  show- 
ing an  English  sailor  and  a  Patagonian  as  a  dwarf  beside  a 
giant;  and  for  the  statement  by  the  historian  of  Magellan's 
voyage,  that  their  tallest  sailor  only  came  up  to  the  waist  of  the 
first  man  they  met.  It  is  now  known  that  the  average  height 
of  Patagonian  men  is  about  five  feet  ten  inches  or  five  feet 
eleven  inches,  and  none  have  been  found  to  exceed  six  feet  four 
inches.  Photography  would  have  saved  us  from  such  an  error 
as  this. 

There  will  always  be  work  for  good  artists,  especially  in  the 
domain  of  color  and  of  historical  design ;  but  the  humblest  pho- 
tographer is  now  able  to  preserve  for  us,  and  for  future  genera- 
tions, minutely  accurate  records  of  scenes  in  distant  lands,  of 
the  ruins  of  ancient  temples  which  are  sometimes  the  only 
record  of  vanished  races,  and  of  animals  or  plants  that  are 
rapidly  disappearing  through  the  agency  of  man.  And,  what 
is  still  more  important,  they  can  preserve  for  us  the  forms  and 
faces  of  the  many  lower  races  which  are  slowly  but  surely 
dying  out  before  the  rude  incursions  of  our  imperfect  civilization. 

Among  the  numerous  scientific  discoveries  of  our  century 
we  must  give  a  very  high,  perhaps  even  the  highest,  place  to 
spectrum  analysis.  Not  only  because  it  has  completely  solved 
the  problem  of  the  true  nature  and  cause  of  the  various  spec- 
tra produced  by  different  kinds  of  light,  but  because  it  has 
given  us  a  perfectly  new  engine  of  research,  by  which  we  are 
enabled  to  penetrate  into  the  remotest  depths  of  space,  and 
learn  something  of  the  constitution  and  the  motions  of  the  con- 
stituent bodies  of  the  stellar  universe.  Through  its  means  we 


LIGHT  AND  ITS   WES  109 

have  acquired  what  are  really  the  equivalents  of  new  senses, 
which  give  us  knowledge  that  before  seemed  absolutely  and 
forever  unattainable  by  man. 

The  solar  spectrum  is  that  colored  band  produced  by  allow- 
ing a  sunbeam  to  pass  through  a  prism,  and  a  portion  of  it  is 
given  by  the  dewdrop  or  the  crystal  when  the  sun  shines  upon 
them ;  while  the  complete  band  is  produced  by  the  numerous 
raindrops,  the  colored  rays  from  which  form  the  rainbow. 
Newton  examined  the  colors  of  the  spectrum  very  carefully, 
and  explained  them  on  the  theory  that  light  of  different  colors 
has  different  refrangibilities — or,  as  we  now  say,  different  wave 
lengths.  He  also  showed  that  a  similar  set  of  colors  can  be 
produced  by  the  interference  of  rays  when  reflected  from  the 
two  surfaces  of  very  thin  plates,  as  in  the  case  of  what  are 
termed  Newton's  rings  and  in  the  iridescent  colors  of  thin 
films  of  oil  on  water,  of  soap  bubbles,  and  many  other  sub- 
stances. 

These  color  phenomena,  although  very  interesting  in  them- 
selves, and  giving  us  more  correct  ideas  of  the  nature  of  color 
in  the  objects  around  us,  did  not  lead  to  anything  further.  But 
in  1802,  the  celebrated  chemist,  Dr.  Wollaston,  made  the  re- 
markable discovery  that  the  solar  spectrum,  when  closely  ex- 
amined, is  crossed  by  very  numerous  black  lines  of  various 
thicknesses,  and  at  irregular  distances  from  each  other.  Later, 
in  1817,  these  lines  were  carefully  measured  and  mapped  by 
Fraunhof er ;  but  their  meaning  remained  an  unsolved  problem 
till  about  the  year  1860,  when  the  German  physicist,  Kirch- 
hoff;  discovered  the  secret,  and  opened  up  to  chemists  and 
astronomers  a  new  engine  of  research  whose  powers  are  prob- 
ably not  yet  exhausted. 

It  was  already  known  that  the  various  chemical  elements, 
when  heated  to  incandescence,  produce  spectra  consisting  of  a 
group  of  colored  bands,  and  it  had  been  noticed  that  some  of 
these  bands,  as  the  yellow  band  of  sodium,  corresponded  in 
position  with  certain  black  lines  in  the  solar  spectrum.  Kirch- 
hoffs  discovery  consisted  in  showing  that,  when  the  light  from 
an  incandescent  body  passes  through  the  same  substance  in  a 
state  of  vapor,  much  of  it  is  absorbed,  and  the  colored  bands 


110  ACHIEVEMENTS  IN  SCIENCE 

become  replaced  by  black  lines.  The  black  lines  in  the  solar 
spectrum  are  due,  on  this  theory,  to  the  light  from  the  incan- 
descent body  of  the  sun  being  partially  absorbed  in  passing 
through  the  vapors  which  surround  it.  This  theory  led  to  a 
careful  examination  of  the  spectra  of  all  the  known  elements, 
and  on  comparing  them  with  the  solar  spectrum  it  was  found 
that  in  many  cases  the  colored  bands  of  the  elements  corre- 
sponded exactly  in  position  with  certain  groups  of  black  lines 
in  the  solar  spectrum.  Thus  hydrogen,  sodium,  iron,  magne- 
sium, copper,  zinc,  calcium,  and  many  other  elements  have  been 
proved  to  exist  in  the  sun.  Some  outstanding  solar  lines,  which 
did  not  correspond  to  any  known  terrestrial  element,  were  sup- 
posed to  indicate  an  element  peculiar  to  the  sun,  which  was 
therefore  named  helium.  Quite  recently  this  element  has 
been  discovered  in  a  rare  mineral,  and  its  colored  spectrum  is 
found  to  correspond  exactly  to  the  dark  lines  in  the  solar  spec- 
trum on  which  it  was  founded,  thus  adding  a  final  proof  of  the 
correctness  of  the  theory,  and  affording  a  striking  example  of 
its  value  as  an  instrument  of  research. 

The  immediate  effect  of  the  application  of  the  spectroscope 
to  the  stars  was  very  striking.  The  supposition  that  they  were 
suns  became  a  certainty,  since  they  gave  spectra  similar  in 
character  and  often  very  closely  resembling  in  detail  that  of 
our  sun. 


LIGHT  AND  ITS  USES 


Color 

By  ELISHA  GRAY 

IN  the  musical  scale  each  note  differs  from  the  other  in  the 
matter  of  pitch ;  and  pitch,  as  we  have  seen,  is  the  rate  of 
vibration  per  second.  Colors  differ  in  pitch  the  same  as  musi- 
cal tones,  and  there  are  about  an  octave  of  them.  If  we  allow 
a  beam  of  sunlight  to  come  into  a  dark  room  through  a  small 
aperture  and  let  it  fall  on  a  white  screen,  there  will  appear  a 
round  spot  of  white  light  that  is  an  image  of  the  sun.  If  now 
we  intercept  the  beam  of  light  with  a  prism  placed  with  the 
edge  downward,  there  will  appear  on  the  screen  a  band  of  colors, 
one  above  the  other.  They  will  appear  in  the  following  order, 
beginning  at  the  bottom:  Red,  orange,  yellow,  green,  blue, 
indigo,  violet,  and  the  whole  is  called  the  solar  spectrum. 
When  a  ray  of  light  passes  from  a  rarer  to  a  denser  medium — 
as  from  air  through  glass — the  rays  are  bent  out  of  their  course, 
and  the  bend  is  different  for  each  color.  This  bend  is  called 
refraction.  The  red  ray  is  the  least  refracted  and  the  violet 
the  most ;  and  this  is  why  the  violet  appears  at  the  top  of  the 
band  of  colors.  This  difference  of  bend  in  the  color  rays  is 
due  to  the  difference  of  wave  length.  For  light,  like  sound, 
has  a  definite  wave  length  for  each  vibration  period.  In  order 
that  we  may  better  understand,  let  us  go  back  a  little  and  tabu- 
late the  vibration  period  of  each  color : 

Red 477,000,000,000,000  per  second 

Orange 506,000,000,000,000  per  second 

Yellow 535,000,000,000,000  per  second 

111 


112  ACHIEVEMENTS  IN  SCIENCE 

Green 577,000,000,000,000  per  second 

Blue 622,000,000,000,000  per  second 

Indigo 658,000,000,000,000  per  second 

Violet 699,000,000,000,000  per  second 

It  will  be  seen  from  the  foregoing  table  that  the  vibration 
rate  per  second  increases  from  red  to  violet.  The  wave  length 
of  the  slowest  vibration,  to  wit,  red,  is  the  greatest,  the  same 
as  in  sound,  and  the  shortest  is  that  of  the  most  rapid — violet. 
The  more  waves  there  are  in  a  given  distance  the  greater  the 
bend  will  be  in  passing  from  one  medium  to  another. 

The  red  ray  has  39,000  waves  to  an  inch,  hence  the  wave 
length  of  red  is  one  thirty-nine-thousandth  of  an  inch.  The 
violet  ray  has  57,000  waves  to  the  inch.  The  red  ray,  having 
the  fewest  number  of  waves  to  the  inch,  is  therefore  bent  out 
of  its  course  the  least,  while  the  violet  ray,  having  the  greatest 
number  per  inch,  is  bent  the  most  out  of  its  course  in  passing 
through  the  prism.  It  will  be  seen  from  the  foregoing  why  the 
colors  are  dispersed  in  passing  through  the  prism. 

It  will  be  remembered  that  the  wave  length  of  a  sound  tone 
with  256  vibration  periods  per  second  was  four  feet  and  four 
inches  in  air.  It  will  be  noted  that  there  is  a  vast  difference 
between  the  wave  length  of  a  sound  tone  and  that  of  a  color  tone. 

You  ask,  why  do  different  objects  seem  to  have  different 
colors  ?  Color  as  a  sensation  is  the  effect  of  ether  waves  im- 
pinging upon  the  retina  of  the  eye.  When  these  waves  enter 
the  eye  at  the  rate  of  477,000,000,000,000  per  second  there  is  a 
sensation  produced  in  the  brain  that  we  call  red,  but  when  the 
retina  is  agitated  by  699,000,000,000,000  ether  waves  per  second 
we  experience  the  sensation  of  violet,  and  the  same  is  true  of 
the  other  colors ;  so  that  for  each  variation  of  rate  within  the 
limits  of  color  there  will  be  a  corresponding  variation  of  color 
sensation.  Having  now  established  the  rates  of  motion  and 
the  wave  lengths  of  the  different  colors  of  light,  we  are  pre- 
pared to  explain  the  phenomena  of  color  as  they  appear  on  vari- 
ous objects  that  come  within  the  range  of  our  vision. 

It  has  been  stated  in  a  preceding  chapter  that  we  see  all 
non-luminous  objects  by  reflected  light.  If  a  ray  of  white  light 


LIGHT  AND  ITS   USES  113 

falls  upon  a  black  surface,  all  the  colors  are  absorbed  and  none 
reflected.  Darkness  is  the  absence  of  light,  hence  we  have 
black,  which  is  simply  the  absence  of  all  color.  If  a  ray  of 
light  falls  upon  an  object  that  absorbs  all  the  colors  but  red, 
then  red  alone  will  be  reflected  to  the  eye  and  we  have  the  sen- 
sation which  belongs  to  that  color,  because  the  rate  of  vibra- 
tion that  produces  this  sensation  of  red  is  the  only  one  that  is 
reflected.  This  same  thing  would  be  true  of  all  the  colors.  If 
an  object  has  a  violet  color  it  is  because  all  the  other  colors 
are  absorbed  and  violet  only  is  reflected  to  the  eye,  hence  the 
sensation  of  violet. 

When  a  color  is  absorbed  it  becomes  heat.  If  we  wear  dark 
clothing  the  sun  will  seem  much  hotter  than  when  we  are 
clothed  in  white.  The  former  absorbs  the  color  vibrations, 
which  become  heat,  while  the  latter  reflects  them.  If  we  have 
some  color  tint  which  arises  from  a  mixture  of  colors,  it  is  be- 
cause the  object  so  tinted  is  able  to  reflect  two  or  more  color 
vibrations,  the  resultant  of  which  is  the  tint.  Colors,  like 
sounds,  may  be  mixed  in  an  infinite  number  of  proportions,  and 
each  change  of  proportion  is  not  only  a  change  of  the  physical 
conditions  of  the  ether  between  the  reflecting  substance  and 
the  eye,  but  a  change  of  sensation,  or  emotion.  The  blending 
of  color  motion  affects  our  emotional  nature  somewhat  as  the 
blending  of  sonorous  tones  does.  They  may  be  harmonious 
and  pleasing,  or  they  may  be  inharmonious  and  irritating. 
Women  are  as  a  rule  more  sensitive  to  color  tints  than  men, 
because  their  training  has  been  such  as  to  make  them  so.  We 
hear  them  say,  "  Those  colors  fight,"  which  is  another  way  of 
saying  that  they  are  inharmonious  and  grate  upon  their  sensi- 
tive nerves. 

Color  art  is  not  yet  developed  so  that  it  is  a  language  of  the 
emotions  in  the  same  sense  that  music  is.  Not  long  ago  it 
could  have  been  said  that  music  was  not  an  art.  It  may  be 
that  at  some  future  time  the  art  of  color,  so  crudely  developed 
now,  will  be  brought  to  the  same  state  of  perfection  as  a  lan- 
guage for  the  expression  of  emotion  that  the  art  of  music  has 
reached  at  the  present  time. 

It  will  be  impossible  to  give  you  more  than  a  very  few  fun- 
8 


114  ACHIEVEMENTS  IN  SCIENCE 

damental  facts  relating  to  this  beautiful  science,  because  so 
many  of  the  phenomena,  to  be  understood  intelligently,  need 
the  aid  of  experiment  and  illustration  that  cannot  be  had  here. 
The  fundamental  thought  running  through  all  the  phenomena 
of  sound,  heat,  and  light,  as  well  as  electricity,  is  motion ;  mo- 
tion, as  related  to  our  sense  perceptions,  and  motion  as  related 
to  all  the  innumerable  phenomena  of  nature. 

Let  us  now  continue  our  investigation  of  color,  from  the 
standpoint  of  definite  rates  of  motion  and  definite  lengths'  of 
impulse.  Every  schoolboy  is  familiar  with  soap  bubbles,  and 
has  spent  many  a  happy  hour  blowing  them.  But  he  did  not 
realize  how  many  scientific  truths  could  be  extracted  from 
them.  The  study  of  soap  bubbles  has  led  to  some  of  the  great- 
est discoveries. 

The  great  Sir  Isaac  Newton  made  some  of  his  most  impor- 
tant discoveries  by  studying  soap  bubbles.  Day  after  day  he  sat 
in  his  back  yard  blowing  them  and  watching  them  rise  in  the 
air,  displaying  those  varied  hues  of  color  that  any  one  may  see 
by  trying  the  experiment.  His  neighbors  became  alarmed  and 
took  council  among  themselves  as  to  what  should  be  done  for 
the  "  poor  man."  Poor,  indeed,  he  was  to  those  ignorant  souls. 
But  how  rich  was  his  life  to  the  millions  who  have  followed  him ! 

For  getting  the  finest  results  in  the  formation  of  soap  bub- 
bles, the  best  medium  is  a  solution  of  castile  soap  and  glycerine 
in  the  proportion  of  one  part  glycerine  to  two  of  the  saturated 
solution  of  soap.  First,  take  a  common  glass  tumbler  and  dip 
the  mouth  of  it  into  the  solution,  and  by  careful  handling  we 
can  get  a  film  of  soap  and  glycerine  stretched  across  the  mouth 
of  the  tumbler.  Now  turn  the  tumbler  over  on  its  side  and 
immediately  bands  of  color  will  appear  running  across  the  film. 
You  will  notice  that  these  colors  change.  We  have  already 
seen  that  every  color  has  a  definite  wave  length  and  a  definite 
rate  of  vibration  per  second.  A  color  will  be  reflected  from 
the  film  when  its  thickness  is  one-fourth  of  the  wave  length 
that  belongs  to  that  color.  We  saw  that  when  sound  was  re- 
flected or  reenforced  by  a  hollow  tube  closed  at  one  end,  the 
tube  was  one-fourth  the  length  of  the  sound  wave.  The  same 
law  holds  good  with  color  motion.  The  reflection  is  from  the 


LIGHT  AND  ITS   USES  115 

back  of  the  film,  as  sound  is  from  the  bottom  of  the  tube.  If 
the  film  is  thick  enough,  the  first  color  that  will  appear  is  red, 
and  after  that  the  others  in  the  order  of  their  succession  in  the 
solar  spectrum.  The  film  is  constantly  growing  thinner  at  the 
top,  by  the  stretching  produced  by  gravity,  and  when  it  reaches 
the  thickness  of  one  one-hundred-and-fifty-six-thousandth  of 
an  inch  the  red  ray  will  appear,  as  that  is  one-fourth  the  wave 
length  of  the  red  ray.  When  all  the  phases  of  color  have  ap- 
peared and  passed  down,  there  appears  a  patch  of  gray  at  the 
top  of  the  film  which  tells  us  that  it  is  stretched  to  its  limit. 
And  now  it  breaks.  Knowing  as  we  do  the  wave  lengths  of 
color,  we  are  able  to  measure  the  thickness  of  the  film.  If 
violet  has  appeared  on  the  film  we  know  that  it  is  not  over  one- 
fourth  the  thickness  of  a  wave  length  of  that  color,  which  would 
be  one  two-hundred-and-twenty-eight-thousandth  of  an  inch. 
This  gives  us  also  some  idea  of  the  size  of  a  molecule  of  water, 
as  the  film  cannot  stretch  to  a  thinness  beyond  the  diameter  of 
the  molecule ;  although  the  film  may  break  by  its  own  weight 
long  before  its  thickness  has  been  reduced  to  that  diameter. 

Light  waves  may  be  made  to  interfere  with  each  other  the 
same  as  sound  waves.  If  two  sets  of  light  waves  of  the  same 
wave  length  are  so  related  to  each  other  that  one  set  of  waves 
falls  in  the  depression  between  the  other  set,  the  result  is  dark- 
ness. 

We  have  seen  that  if  all  the  colors  of  a  sunbeam  are  totally 
reflected  to  the  eye  from  an  object,  the  color  of  the  object  is 
white.  But  if  some  one  of  the  colors  is  only  partially  reflected 
or  entirely  absorbed,  the  composite  effect  would  be  something 
away  from  white.  There  is  an  inconceivable  number  of  varia- 
tions and  proportions  of  color,  and  as  each  variation  may  pro- 
duce a  variation  of  tone,  or  tint,  we  can  see  how  all  the  delicate 
shadings  of  a  poem  or  a  symphony  in  color  may  be  produced. 
Some  time  color  and  color  tones  may  be  classified  and  arranged 
in  their  order  of  succession  and  combination,  and  by  some  sort 
of  instrument  that  will  cause  them  to  appear  and  disappear — 
played  upon  as  we  do  upon  a  musical  instrument  to  produce  the 
effect  of  sound  coloring.  Color  will  then  become  a  language  of 
emotion,  as  music  is  now. 


LIGHT  AND  ITS  USES 


The  X-Rays 

By  JOHN  TROWBRIDGE* 

SINCE  the  publication  of  Hertz's  paper  on  the  penetration 
of  thin  sheets  of  metal,  notably  aluminum,  by  the  cathode 
rays,  interest  in  the  remarkable  phenomena  investigated  first 
by  Professor  Crookes  has  been  reawakened  to  a  marked  degree ; 
and  most  physicists  during  the  past  five  years  have  regarded 
the  subject  of  cathode  rays  as  the  most  important  one  in  elec- 
tricity. In  1893  Lenard  succeeded,  by  means  of  a  Crookes 
tube  provided  with  a  small  aluminum  window,  in  detecting  the 
cathode  rays  outside  the  tube  in  the  air  space  of  an  ordinary 
room.  He  used  paper  disks  covered  with  a  very  fluorescent 
substance,  which  became  luminous  when  the  cathode  rays 
struck  them ;  and  he  also  succeeded  in  showing  photographic 
effects  of  the  rays.  Now  Rontgen,  by  the  use  of  ordinary  dry 
plates  and  without  the  use  of  an  aluminum  window,  has  taken 
photographs  through  wood  and  through  the  human  hand  by 
means  of  what  he  terms  the  ;r-rays,  which  he  supposes  are  ex- 
cited either  in  the  glass  walls  of  the  Crookes  tube  or  in  the 
media  outside  the  tube  by  means  of  the  cathode  rays. 

We  see,  therefore,  that  the  literature  of  the  subject  must 
be  sought  in  the  papers  of  Crookes,  Hertz,  Lenard,  and  Ront- 
gen ;  and  the  interest  in  the  mysterious  manifestations  of  these 
invisible  rays  is  twofold ;  first,  in  regard  to  the  possible  applica- 
tion of  the  phenomena  to  surgery,  since  the  rays  show  a  specific 
absorption,  passing  more  easily  through  the  flesh  than  through 


*  Rumford  Professor  at  Harvard  University. 

116 


LIGHT  AND  ITS   USES  117 

bones  or  glass  or  metallic  particles ;  and,  secondly,  in  relation 
to  the  questions  whether  we  are  dealing  here  with  radiant  mat- 
ter shot  forth  from  the  negative  pole  or  cathode  or  with  longi- 
tudinal waves  of  electricity. 

Let  us  examine  the  possibility  of  the  practical  application  of 
the  cathode  photography  to  surgery.  The  term  cathode  is  ap- 
plied to  the  zinc  pole  or  negative  pole  of  an  ordinary  battery.  It 
is  that  terminal  of  an  electrical  machine  which  glows  least  in  the 
dark  when  the  machine  is  excited.  It  is  the  shortest  carbon  in 
the  ordinary  street  electric  lamp.  The  positive  carbon  or 
anode  burns  away  twice  as  fast  as  the  negative  carbon  or 
cathode.  If  the  electric  light  is  formed  in  a  high  vacuum  by 
means  of  a  great  electro-motive  force,  we  no  longer  have  a 
voltaic  arc  or  a  spark ;  instead  of  this  the  exhausted  vessel  is 
filled  with  a  feeble  luminosity,  and  a  beam  of  bluish  rays  is 
seen  to  stream  from  the  negative  terminal  or  cathode.  When 
these  rays  strike  the  glass  walls  of  the  vessel  they  excite  a 
strong  fluorescence.  If  the  glass  contains  an  oxide  of  uranium, 
this  fluorescence  is  yellow ;  if  it  contains  an  oxide  of  copper,  it 
is  green.  Rontgen  supposes  that  this  fluorescence  excited  by 
the  cathode  rays  is  connected  in  some  way  with  the  formation 
of  what  he  terms  the  -r-rays.  Now,  a  photograph  of  the  bones 
in  the  hand,  for  instance,  can  be  obtained  by  placing  a  sensitive 
plate  in  an  ordinary  photographic  plate-holder.  Resting  the 
hand  on  the  undrawn  slide  in  the  daylight,  with  the  palm  of  the 
hand  outward  and  toward  the  cathode,  and  about  six  inches 
away  from  it,  the  bones  of  the  hand  are  thus  brought  in  the 
nearest  possible  position  to  the  sensitive  plate.  At  the  time  of 
the  present  writing,  the  breast  and  the  abdomen  of  trie  human 
body  present  too  great  thickness  for  successful  photographs, 
and  the  attempts  to  obtain  representations  of  the  cavity  in 
which  the  brain  is  situated  have  been  failures,  since  the  rays 
do  not  show  any  marked  difference  in  fleshy  tissues.  Nothing 
can  be  obtained  in  these  attempts  to  photograph  the  brain  but 
a  contour  of  the  cavity  in  which  it  is  situated,  and  possibly  a 
shadowy  representation  of  a  bullet  which  might  be  imbedded  in 
the  head.  The  method  of  obtaining  a  successful  photograph 
of  the  hand  shows  the  present  limitations  of  the  method.  In 


118 


ACHIEVEMENTS  IN  SCIENCE 


order  to  obtain  a  fairly  sharp  shadow  of  a  bone  or  of  a  shot,  it 
should  not  be  more  than  an  inch  away  from  the  sensitive  plate. 
The  term  shadow,  however,  is  somewhat  misleading.  The 
photograph  of  the  hand  by  the  ^r-rays  is  entirely  different  from 
one  produced  by  resting  the  hand  in  a  similar  position  to  that 
above  described  against  an  uncovered  sensitive  plate  in  a  dark 
room  and  then  lighting  a  match.  By  the  last  method  we  should 
obtain  a  true  shadow  of  the  hand,  the  flesh  would  throw  as  dense 
a  shadow  as  the  bones,  and  the  latter  could  not  be  detected  in 
the  general  blackness.  In  the  cathode  photograph,  on  the 
other  hand,  a  difference  in  absorptive  power  is  shown :  the  flesh 
looks  like  a  hazy  film  around  the  skeleton,  and  even  the  medulla 
cavities  can  be  made  out,  and  the  varying  thickness  of  the 
bones  is  more  or  less  shown.  This  specific  absorption  is  of 
great  scientific  interest  as  well  as  of  practical  importance. 

Now,  these  ;r-rays  will  penetrate  several  inches  of  wood, 
with  varying  amount  of  absorption,  but  they  are  almost  entirely 
cut  off  by  glass  as  thick  as  a  window  pane.  They  pass  through 
thin  layers  of  aluminum,  even  layers  as  thick  as  a  silver  ten- 
cent  piece,  while  the  silver  coin  almost  entirely  intercepts 
them. 

It  therefore  immediately  occurs  to  one,  Why  not  return  to 
Lenard's  tube,  provide  a  Crookes  tube  with  an  aluminum  win- 
dow, and  thus  save  the  great  absorption  of  the  glass  walls  of 
the  tube  ?  There  are  certain  practical  difficulties  in  the  way. 
The  aluminum  must  be  very  thin.  Lenard  used  a  window 
which  was  about  one  eight-thousandth  of  an  inch  thick,  and  it 
was  necessarily  very  small,  in  order  to  stand  the  atmospheric 
pressure.  An  aluminum  window  one  eighth  of  an  inch  thick, 
or  as  thick  as  a  ten-cent  piece,  would  absorb  nearly  as  much  as 
the  glass  walls  of  the  present  forms  of  Crookes  tubes,  which 
are  not  more  than  one  sixtieth  of  an  inch  thick.  Glass  vessels 
seem  at  present  to  be  more  practical  than  any  composite  form, 
in  which  aluminum  is  glued  to  a  glass-supporting  vessel :  first, 
because  it  can  be  blown  very  thin,  and  in  a  shape  strong 
enough  to  withstand  the  atmospheric  pressure;  secondly,  be- 
cause the  occluded  air  can  be  more  effectively  driven  off  the 
inner  walls  of  the  vessels  by  heating  it  while  it  is  being  ex- 


LIGHT  AND  ITS   USJE8  119 

hausted  than  it  can  be  expelled  from  a  vessel  of  any  other 
material. 

To  obtain  successful  photographs,  the  exhaustion  of  the  air 
must  be  pushed  to  a  high  degree ;  and  this  is  also  interesting 
from  the  scientific  point  of  view.  Moreover,  a  high  electro- 
motive force  is  necessary.  Pictures  can  be  taken  in  less  than 
one  minute  of  the  skeleton  of  the  human  hand  by  means  of 
high  vacua  tubes  excited  by  high  electro-motive  force.  Even 
in  this  bare  recital  of  the  present  limits  of  the  application  of 
the  ;r-rays  to  photography,  we  perceive  great  possibilities  in 
the  application  of  the  method  to  the  surgery  of  the  human  ex- 
tremities. There  is  no  doubt  that  small  foreign  bodies,  like 
shot  and  pieces  of  glass,  can  be  detected  in  the  fleshy  tissues 
of  the  hand.  Certain  accessible  regions  of  the  body,  like  the 
mouth,  can  possibly  be  examined  by  placing  a  sensitive  film 
inside  the  mouth  and  the  cathode  outside  of  the  cheek ;  and  it 
does  not  seem  improbable  that  a  suitable  cathode  vessel  can  be 
inserted  into  certain  abdominal  regions  and  a  photograph  be 
obtained  by  placing  a  sensitive  plate  on  the  outside  of  the  body. 
By  employing  two  cathodes,  at  the  proper  distance  apart,  stere- 
oscopic representations  of  the  bones  can  be  obtained,  and  an 
estimate  formed  of  the  position  of  foreign  bodies. 

Let  us  now  turn  to  some  of  the  interesting  scientific  ques- 
tions which  have  arisen  in  regard  to  this  apparently  new  mani- 
festation of  the  cathode  rays.  In  the  first  place,  they  are 
apparently  not  refracted  by  paraffine,  vulcanite,  or  wood,  or  by 
any  substance  which  is  penetrated  by  them.  To  test  this,  I 
employed  a  double-convex  lens  of  wood  and  also  a  double-con- 
cave lens  of  the  same  material.  I  placed  two  copper  rings  in 
the  concavity  of  the  double-concave  lens  of  wood,  and  also  a 
similar  copper  ring  outside  the  lens  at  the  same  height  from 
the  sensitive  plate,  as  one  of  the  rings  which  rested  on  the 
wood  of  the  lens.  I  also  placed  a  ring  on  the  double-convex 
lens,  and  employed  two  cathodes  to  obtain  two  shadows  from 
different  positions.  The  thickness  of  the  wooden  lenses  varied 
from  half  an  inch  to  three  quarters  of  an  inch.  The  images 
obtained  through  the  wood  of  the  lenses  were  not  distorted  or 
changed  in  figure  in  any  way  by  the  wood,  and  therefore  no 


120 


ACHIEVEMENTS  IN  SCIENCE 


•refraction  could  be  observed  by  this  method.  On  account  of 
the  quick  diffusibility  of  the  rays,  no  accurate  method  of  deter- 
mining a  possible  index  of  refraction  seems  possible.  If  the 
photographic  effect  is  due  to  longitudinal  waves  in  the  ether, 
and  if  these  waves  travel  with  great  velocity,  no  refraction 
would  probably  be  observed.  Maxwell's  electro-magnetic  the- 
ory of  light  supposes  that  only  transverse  waves  are  set  up 
in  the  ether,  and  no  longitudinal  waves  exist.  On  the  other 
hand,  Helmholtz's  electro-magnetic  theory  of  light  postulates 
longitudinal  waves  as  well  as  transverse  waves.  The  longitu- 
dinal waves  travel  with  an  infinite  velocity.  Is  it  therefore 
possible  that  the  ^r-waves  are  the  longitudinal  waves  of  Helm- 
holtz's theory?  Our  apparent  inability  to  refract  the  rays 
lends  color  to  this  hypothesis.  Rontgen,  in  the  preliminary  ac- 
count of  his  experiments,  intimates  that  the  phenomena  may  be 
due  to  longitudinal  waves,  and  in  a  late  article  in  the  "  Annalen 
der  Physik  und  Chemie,"  by  Jaumann,  entitled  "  Longitudinal 
Light,"  Maxwell's  electro-magnetic  equations  are  modified  so 
as  to  embrace  the  phenomenon  of  cathode  rays ;  and  the  author 
shows  that  even  Maxwell's  theory  can,  under  certain  conditions, 
give  a  longitudinal  wave. 

The  Rontgen  phenomenon  seems  to  be  a  manifestation  of 
cathode  rays  brought  to  light  and  endowed  with  great  practical 
interest  by  its  application  to  dry-plate  photography.  When  we 
return  to  the  classical  investigation  of  Lenard  mentioned  in  the 
beginning  of  this  article,  we  are  impressed  by  an  apparently 
crucial  experiment  which  he  describes  in  regard  to  the  exist- 
ence of  an  ether.  He  caused  the  cathode  beam  to  pass  out  of 
his  high  vacua  through  an  aluminum  window  into  another  tube 
about  three  feet  long,  which  had  been  exhausted  to  such  a  high 
degree  that  no  electrical  discharge  would  pass  through  it.  It 
seemed,  therefore,  to  have  an  infinite  electrical  resistance.  No 
cathode  beam  could  be  generated  in  it ;  nevertheless,  by  mov- 
ing suitable  disks  of  fluroescent  matter  from  point  to  point  in 
the  tube  by  means  of  an  outer  magnet  which  attracted  bits  of 
iron  on  the  disks,  Lenard  showed  that  the  cathode  beam  passed 
through  the  vacuum.  Energy  passed  into  the  vacuum  and 
could  be  detected  from  point  to  point.  We  can  conceive  of 


LIGHT  AND   ITS    USES 


121 


its  passing  through  the  ether  in  the  tube  by  a  wave  motion,  but 
not  by  a  molecular  movement,  for  there  were  no  molecules  to 
move.  The  molecular  bombardment  must  have  stopped  at  the 
aluminum  window,  and  the  resulting  energy  may  have  been 
propagated  by  ripples  in  the  ether.  This  experiment  of  Lenard 
seems  to  me  the  most  interesting  one  in  the  subject  of  cathode 
rays.  The  greatest  mystery,  however,  which  envelops  the  sub- 
ject is  the  action  of  the  .r-rays  on  bodies  charged  with  elec- 
tricity. When  the  rays  fall  on,  for  instance,  a  charged  pith 
ball,  the  charge  disappears.  A  positive  as  well  as  a  negative 
charge  is  dispelled  by  the  ^r-rays.  The  energy  of  the  medium 
about  the  pith  ball  is  changed  to  a  marked  degree,  and  in  this 
phenomenon  we  seem  to  be  brought  closer  to  a  wave  theory  in 
a  medium  than  to  a  molecular  theory  of  movement  of  matter. 


LIGHT  AND  ITS  USES 


X-Ray  Photography 

By  RAY  STANNARD  BAKER 

T)ERHAPS  no  inventor  ever  achieved  world-wide  distinction 
JL  so  quickly  as  Dr.  William  Konrad  Rontgen.  He  dis- 
covered his  famous  ;r-rays  on  November  8,  1895;  in  December 
he  described  them  before  the  Wiirzburg  Physico-Medical  So- 
ciety ;  in  January  the  marvel  of  the  new  rays  which  penetrate 
and  photograph  through  almost  every  known  substance  was 
known  all  over  the  world,  as  well  to  newspaper  readers  as  to 
the  learned  societies.  A  few  months  later  many  prominent 
scientists  both  in  Europe  and  in  America,  were  experimenting 
with  Rontgen' s  rays,  and  within  a  year  they  had  become  a  regu- 
lar and  exceedingly  important  factor  in  surgical  operations. 
Moreover,  no  one  disputed  the  originality  of  Dr.  Rontgen's 
discovery ;  he  had  invented  the  first  machine  for  photographing 
through  solid  substances,  for  taking  pictures  of  the  skeleton 
framework  of  the  human  body  through  the  flesh.  No  one  ever 
before  had  done  that,  and  the  scientific  world  was  quick  with 
its  appreciation  and  liberal  with  its  honors. 

And  yet  this  discovery,  which  many  scientists  rank  side  by 
side  with  Lister's  system  of  antiseptics  in  its  importance  as  a 
life  saver,  was  not  the  result  of  happy  chance.  It  was  not 
mere  luck.  At  the  time  that  Dr.  Rontgen  saw  the  ^r-rays 
shimmering  and  glowing  for  the  first  time  on  a  bit  of  sensitive 
paper  he  was  past  fifty  years  old,  and  during  the  greater  part 
of  his  life  he  had  been  working  quietly  but  industriously  and 
thoughtfully  with  the  great  problems  of  physics  and  electricity. 
He  laid  the  foundation  of  his  career  in  a  thorough  education  at 

122 


LIGHT  AND  1?S  USES  123 

Zurich,  his  birthplace,  and  at  Utrecht.  Seven  years  before  the 
discovery  he  had  become  a  professor  at  the  Royal  University 
in  the  quaint  old  Bavarian  town  of  Wiirzburg.  Here,  in  a  bare 
little  laboratory  in  an  equally  modest  two-story  house,  with  few 
of  the  modern  appliances,  he  made  his  famous  experiments, 
and  from  here  he  went  out,  when  the  world  heard  of  him,  to 
receive  the  praise  and  decorations  of  his  emperor.  And  after 
that  he  returned  to  his  work,  just  as  if  he  wasn't  famous. 

Dr.  Rontgen  (pronounced  Rentgen)  is  a  tall,  slender,  some- 
what loosely  built  man,  with  a  bushy  beard  and  long  hair  rising 
straight  up  from  a  high  white  forehead.  When  he  is  excited 
or  much  in  earnest  he  thrusts  his  fingers  through  this  mass  of 
hair  until  it  bristles  all  over  his  head.  He  has  an  amiable  face 
with  kindly  although  penetrating  eyes.  His  voice  is  full  and 
deep,  and  he  speaks  with  the  rapidity  of  great  enthusiasm.  In- 
deed, his  whole  bearing  tells  of  boundless  energy  and  unremit- 
ting vigor.  One  visitor  compared  him  on  first  sight  to  an 
amiable  gust  of  wind. 

Previous  to  the  discovery  which  made  him  famous,  Dr. 
Rontgen  had  actually  been  producing  and  working  with  ar- 
rays for  some  time  without  knowing  it.  Indeed,  other  scien- 
tists had  been  doing  much  the  same  thing — experimenting  all 
unconsciously  on  the  very  verge  of  the  greatest  discovery  of 
years,  but  it  remained  for  Dr.  Rontgen,  with  his  keener  scien- 
tific insight,  to  see  the  unseen. 

The  famous  electrician  Hertz,  whose  discoveries  have  made 
possible  more  than  one  great  invention,  had  tried  sending  a 
high-pressure  electric  current  through  a  vacuum  tube,  a  so- 
called  Crookes  tube.  A  vacuum  tube  is  a  vessel  of  very  thin 
glass,  having  a  platinum  wire  fixed  in  each  end.  This  vessel 
is  as  nearly  empty  of  everything  as  human  ingenuity  can  make 
it ;  even  the  air  is  pumped  out  until  only  one  one-millionth  of 
an  atmosphere  remains.  Hertz  connected  one  of  these  tubes 
to  the  poles  of  his  battery  by  means  of  the  platinum  wires. 
When  the  discharge  began  he  observed  that  the  anode — that 
is,  the  end  of  the  tube  connected  with  the  positive  pole  of  the 
battery — gave  off  certain  peculiar  and  faint  bands  of  light. 
But  these  were  quite  insignificant  compared  with  the  brilliant 


124 


ACHIEVEMENTS  IN  SCIENCE 


and  beautiful  glow  at  the  other  or  negative  end  of  the  tube, 
which  is  called  the  cathode.  This  glow  resembled  somewhat 
the  fierce  burning  of  an  alcohol  lamp,  only  it  was  softer,  more 
evanescent,  and  more  striking  in  its  coloring.  It  produced  bril- 
liant phosphorescence  in  glass  and  many  other  substances,  and 
Professor  Lenard,  Hertz's  assistant,  observed,  in  1894,  that 
the  rays — "cathode  rays,"  as  they  were  called — would  pene- 
trate thin  films  of  wood,  aluminum,  and  other  substances.  But 
this  was  as  far  as  any  of  the  experimenters  who  preceded  Ront- 
gen  succeeded  in  going. 

Strangely  enough,  both  Hertz  and  Lenard  produced  x- 
rays  in  abundance  without  knowing  it.  These  were,  indeed, 
present  in  the  glow  from  the  cathode,  only  they  were  entirely 
invisible  to  the  human  eye.  They  are  different  from  the  rays 
described  by  Lenard,  in  that  they  are  not  deflected — that  is, 
turned  aside — by  a  magnet,  and  they  are  incomparably  more 
powerful  in  range  and  in  penetrating  power.  It  will  be  seen, 
therefore,  that  while  Dr.  Rontgen  was  not  working  in  a  wholly 
new  field,  his  discovery  is  none  the  less  entirely  original. 

The  discovery  itself  was  made  in  a  peculiarly  interesting 
way.  Dr.  Rontgen  had  been  experimenting  steadily  for  several 
weeks  with  his  Crookes  tubes.  One  day  he  had  covered  the 
tube  with  a  light-excluding  black  shield.  Then  he  had  darkened 
his  laboratory  so  that  not  a  ray  of  light  could  anywhere  enter. 
To  the  eye  everything  was  absolutely  black.  When  the  elec- 
tric current  was  turned  on,  the  hooded  tube  did  not  show  even 
a  glint  of  light ;  but  something  on  a  shelf  below  began  to  glow, 
very  strangely.  It  was  a  piece  of  sensitive  paper — barium 
platino-cyanide  paper.  Dr.  Rontgen  knew  that  no  light  could 
come  from  the  tube,  because  the  shield  that  covered  it  was 
wholly  impervious  to  light — even  the  strongest  electric  light. 
Where,  then,  did  it  come  from  ?  Dr.  Rontgen  began  at  once 
an  eager  investigation,  moving  the  sensitive  paper  from  side  to 
side  and  covering  the  tube  with  a  still  denser  screen.  And 
finally  he  came  to  the  conclusion  that  certain  unknown  rays, 
whether  of  light  or  not,  he  did  not  know,  were  actually  coming 
through  the  screen,  and  giving  the  sensitive  paper  a  distinct 
luminescence.  It  was  contrary  to  all  reason,  to  everything 


LIGHT  AND  ITS   U8JE8  125 

that  the  text-books  taught,  and  yet  Dr.  Rontgen  was  forced  to 
believe  it.  And  having  discovered  the  existence  of  the  new 
rays,  he  began  at  once  to  experiment  with  them.  He  found 
that  they  readily  penetrated  paper,  wood,  and  cloth,  and  that 
the  thickness  of  these  mediums  made  little  difference.  That 
is,  they  would  penetrate  a  thick  book  almost  as  easily  as  they 
would  a  single  sheet  of  paper.  Then  he  tried  photographing, 
and  found  to  his  astonishment  that  the  rays  affected  the  sensi- 
tive film  of  the  photographic  plate,  leaving  the  shadows  of  the 
objects  exposed  plainly  outlined.  For  instance,  he  placed  bits 
of  platinum,  aluminum,  and  brass  inside  of  a  wooden  box,  and 
found  that  not  only  did  he  get  skiagraphs  (shadowgraphs)  of 
them  through  the  wood,  but  all  the  nails  that  held  the  box  to- 
gether and  the  brass  hinges  were  likewise  reproduced.  Then 
he  photographed  a  spool  of  wire,  the  wooden  ends  of  the  spool 
leaving  a  very  faint  shadow,  and  the  wire  a  dark  one.  When 
he  tried  glass,  which  is  one  of  the  most  transparent  of  sub- 
stances so  far  as  ordinary  light  is  concerned,  he  found  that  the 
new  rays  passed  through  it  only  with  difficulty,  and  that  alumi- 
num was  much  more  transparent  to  them  than  glass.  In  other 
words,  if  we  lived  in  an  ^r-ray  world  we  might  use  aluminum 
for  windows  to  let  in  the  ^r-ray  "  light,"  and  glass  for  shutters 
to  keep  it  out. 

After  many  experiments  of  this  kind,  it  suddenly  occurred 
to  Dr.  Rontgen  that  if  the  new  rays  penetrated  all  manner  of 
substances,  they  would  also  penetrate  the  human  body ;  that, 
in  fact,  they  were  probably  going  straight  through  his  hands 
and  his  head  as  he  worked  with  them.  So  he  placed  his  hand, 
palm  down,  on  a  photographic  plate,  still  in  its  black  holder, 
arranged  the  Crookes  tube  above  it,  turned  on  the  current,  and 
in  a  short  time  he  had  a  photograph,  dim,  it  is  true,  but  per- 
fect, of  the  bony  framework  of  his  hand — the  first  of  the  kind 
ever  taken,  and  a  marvel  up  to  that  time  absolutely  incon- 
ceivable. 

A  little  later  he  built  a  closet  of  tin  just  big  enough  to 
accommodate  one  man  comfortably,  and  fitted  it  up  with  an 
aluminum  window.  Outside  of  the  window  he  placed  his  new 
apparatus.  Only  the  new  rays  would,  of  course,  shine  through 


126 


ACHIEVEMENTS  IN  SCIENCE 


the  aluminum,  and  he  could  study  them  at  his  leisure.  But 
after  long  and  careful  experimenting  he  could  not  decide  what 
the  new  rays  really  were,  and  although  many  theories  have 
been  advanced  by  prominent  scientists,  a  really  satisfactory  ex- 
planation is  still  wanting.  It  is  pretty  generally  believed,  how- 
ever, that  Rontgen' s  rays  are  only  a  "  mode  of  motion  "  through 
the  ether — that  is,  they  are  produced  by  a  certain  peculiar  kind 
of  vibration  in  the  ether.  Dr.  Rontgen  himself  gave  them  the 
name  ";tr-rays" — the  unknown  rays. 

But  if  the  exact  nature  of  the  rays  was  a  mystery,  their 
uses  and  importance  became  familiar  almost  immediately.  The 
apparatus  was  so  simple  that  it  could  be  fitted  up  in  almost  any 
laboratory.  It  consisted  merely  of  a  battery  or  dynamo  cur- 
rent ;  a  coil,  usually  a  Rhumkorff  coil,  for  intensifying  the  cur- 
rent, and  a  Crookes  tube,  which  might  have  any  one  of  twenty 
odd  shapes.  As  a  result  of  this  simplicity  thousands  of  sur- 
geons and  scientists  were  able  to  prepare  experimental  appara- 
tus, and  some  of  the  results  in  this  country  were  excellent, 
especially  in  photographing  the  human  skeleton. 

Even  Edison,  the  greatest  of  American  inventors,  took  up 
the  work  with  great  enthusiasm,  and  he  shortly  invented  a  curi- 
ous but  simple  device  by  means  of  which  one  may  actually  see 
the  bones  of  the  hand  or  foot  through  the  flesh.  He  called  it 
the  fluoroscope.  It  is  merely  a  wooden  box,  larger  at  one  end 
than  at  the  other,  the  smaller  end  being  so  constructed  and 
padded  with  cloth  that  it  will  fit  exactly  over  the  eyes  without 
admitting  any  light.  The  other  end  of  the  box  is  covered  with 
a  sheet  of  thin  cardboard  coated  with  a  chemical  compound 
which  becomes  fluorescent — that  is,  shines  or  glows — when 
placed  in  range  of  the  .ar-rays.  By  holding  this  box  between 
one's  eyes  and  a  Crookes  tube,  and  placing  one  hand  on  the 
sensitive  cardboard,  the  ^r-rays  will  readily  pierce  the  flesh, 
and  the  dark  shadow  of  the  skeleton  of  the  hand  may  be  seen. 
In  this  way  a  doctor  can  tell  quickly  the  location  of  a  bullet  or 
a  needle  in  the  hand  or  foot,  for  he  is  able  to  look  through  the 
flesh  as  if  it  were  glass. 

The  Rontgen  rays  have  been  put  to  many  marvelous  uses, 
most  of  them  connected  with  bone  photography  in  surgery 


LIGHT  AND  ITS   USES  127 

cases.  And,  strangely  enough,  when  a  physician  is  ready  to 
photograph  a  broken  arm,  for  instance,  to  see  if  it  is  properly 
set,  he  never  thinks  of  removing  the  splints  or  the  bandages ; 
he  simply  photographs  through  them.  And  that  is  the  reason 
why  such  a  photograph  often  shows  pins  and  buckles.  Fre- 
quently, in  cases  where  the  patient  is  very  weak,  the  photo- 
graph is  taken  through  the  bed-clothes  as  well  as  through  the 
bandages — it  doesn't  make  the  slightest  difference  to  these 
wonderful  rays.  It  takes  from  two  minutes  to  more  than  an 
hour  to  get  a  good  skiagraph,  but  the  operation  is  no  more 
painful,  if  we  count  out  the  necessity  of  keeping  still,  than  hav- 
ing a  snap-shot  taken. 

One  of  the  earliest  skiagraphs,  showing  the  medical  impor- 
tance of  the  jr-rays,  was  taken  in  England.  A  boy  of  nine- 
teen had  injured  his  little  finger  playing  ball,  so  that  it  was 
bent  at  the  last  joint,  and  he  could  neither  extend  it  nor  bend 
it  farther  down.  Any  attempt  to  do  so  caused  him  sharp  pain. 
Before  the  skiagraph  was  taken  the  doctors  declared  that  the 
finger  must  be  amputated.  A  skiagraph  showed,  however, 
that  there  was  only  a  little  bridge  of  bone  uniting  the  last  two 
joints,  thereby  preventing  the  proper  flexing  of  the  finger.  As 
soon  as  this  was  known  an  anaesthetic  was  administered,  and 
by  the  use  of  a  little  force  this  bridge  of  bone  was  snapped,  and 
the  finger  saved.  That  was  the  first  finger  to  the  credit  of  Dr. 
Rontgen's  discovery. 

Since  then  the  ^r-rays  have  been  used  constantly  for  find- 
ing bullets  embedded  in  the  flesh — x-ray  machines  are  now 
taken  to  war  with  every  civilized  army — for  finding  needles 
that  have  been  driven  into  the  foot,  for  examining  deformities 
of  the  bones,  and,  more  recently,  for  photographing  foreign 
bodies  in  the  larynx  and  windpipe,  and  even  in  the  stomach. 
Think  of  the  sufferings  caused  by  probing  for  bullets,  shot,  and 
needles  in  the  flesh,  all  saved  by  an  easily  taken  skiagraph ! 

An  English  woman  came  to  a  doctor  saying  that  she  was 
suffering  tortures  from  her  shoes,  so  that  she  found  it  difficult 
to  walk,  and  she  even  wanted  some  of  her  toes  amputated.  A 
skiagraph  showed  exactly  what  the  trouble  was.  She  had  been 
wearing  shoes  much  too  small  for  her,  and  the  bones  had  be- 


128 


ACHIEVEMENTS  IN  SCIENCE 


come  woefully  twisted  and  bent.  One  sight  of  the  photograph 
convinced  her  that  she  must  wear  broad-soled  shoes.  In  a 
somewhat  similar  case  in  Austria,  the  doctors  found  that  the 
great  toe  of  the  patient  was  twice  as  large  as  it  should  be. 
They  found  by  feeling  that  there  were  two  bones  instead  of 
one,  but  they  could  not  tell  which  was  the  normal  bone  and 
which  the  one  to  be  removed.  A  skiagraph  showed  the  whole 
condition  instantly. 

One  of  the  strangest  uses  to  which  ^r-rays  ever  have  been 
put  was  at  the  instance  of  a  Philadelphia  woman.  She  had 
been  traveling  in  Egypt,  and  had  brought  home  what  she  be- 
lieved to  be  the  hand  of  a  mummy.  But  some  of  her  friends 
told  her  how  Egyptian  curiosities  are  likely  to  be  manufactured 
and  sold  to  unsuspecting  travelers  as  genuine  relics.  One 
friend,  himself  a  great  traveler,  assured  her  that  she  had 
bought  a  mere  mass  of  pitch,  plaster  of  Paris,  and  refuse 
mummy-cloth,  not  a  hand.  For  a  long  time  there  was  no  way 
of  deciding  the  question,  until  at  last  the  owner  of  the  relic  had 
an  ;r-ray  photograph  taken.  And  lo  and  behold !  there  in  the 
picture  was  the  complete  skeleton  of  the  hand  of  some  ancient 
Egyptian;  the  relic  was  genuine,  after  all. 

Another  curious  and  important  use  of  ;r-rays  is  in  deter- 
mining genuine  from  imitation  diamonds.  A  European  scien- 
tist has  made  many  tests  in  this  field,  and  he  finds  that  while 
the  ^r-rays  will  penetrate  the  genuine  diamond  and  leave 
almost  no  shadow  in  the  photograph,  the  false  ones  are  nearly 
opaque  to  the  rays,  and  appear  very  dark  in  the  photograph. 
This  unusual  new  test  may  some  time  supersede  all  others. 

A  great  many  experiments  have  been  made  looking  to  the 
use  of  .r-rays  in  curing  diseases.  Several  prominent  physi- 
cians assert  that  the  new  rays  kill  all  germs — consumption, 
typhoid  fever,  diphtheria,  and  so  on — and  that  by  applying 
them  properly  to  the  diseased  portion  of  the  body  a  cure  may 
be  effected. 


LIGHT  AND  ITS  USES 


The  Eye  as  an  Optical  Instrument 

By  AUSTIN  FLINT* 

I  HAVE  often  wondered  whether  the  statement,  occasionally 
made  by  physicists,  that  the  human  eye  is  not  a  perfect 
optical  instrument,  is  an  expression  of  human  vanity  or  of  an 
imperfect  knowledge  of  the  anatomy  of  the  eye  and  the  physi- 
ology of  vision;  and  I  have  come  to  the  conclusion  that  the 
latter  is  the  more  reasonable  theory.  The  approach  to  perfec- 
tion in  modern  telescopes  and  microscopes  is  wonderful  indeed ; 
but  as  physiologists  have  advanced  the  knowledge  of  vision, 
the  so-called  imperfections  of  the  eye  have  been  steadily  disap- 
pearing ;  and  even  now  there  is  much  to  learn.  Viewed  merely 
as  an  optical  instrument,  an  apparatus  contained  in  a  globe  less 
than  an  inch  in  diameter,  in  which  is  produced  an  image  prac- 
tically perfect  in  form  and  color,  which  can  be  accurately  ad- 
justed almost  instantly  for  every  distance  from  five  inches  to 
infinity,  is  movable  in  every  direction,  has  an  area  for  the  de- 
tection of  the  most  minute  details  and  at  the  same  time  a  suffi- 
cient appreciation  of  large  objects,  is  double,  but  the  images  in 
either  eye  exactly  coinciding,  enables  us  to  see  all  shades  of 
color,  estimate  distance,  solidity,  and  to  some  extent  the  con- 
sistence of  objects,  the  normal  human  eye  may  well  be  called 
perfect.  The  more,  indeed,  the  eye  is  studied  in  detail,  the 
more  thoroughly  does  one  appreciate  its  perfection  as  an  optical 
apparatus. 

Were  it  not  for  a  slight  projection  of  the  cornea  (the  trans- 


Professor  of  Physiology,  Bellevue  Hospital  College,  New  York. 

9  129 


130 


ACHIEVEMENTS  IN  SCIENCE 


parent  covering  in  front)  the  eye  would  have  nearly  the  form 
of  a  perfect  globe  a  small  fraction  less  than  an  inch  in  diameter. 
It  lies  in  a  soft  bed  of  fat,  is  held  in  place  by  little  muscles  and 
a  ligament  which  is  so  lubricated  that  its  movements  take  place 
with  the  minimum  of  friction.  It  is  protected  by  an  overhang- 
ing bony  arch  and  the  eyelids,  the  eyelashes  keeping  away  dust, 
and  the  eyebrows  directing  away  the  sweat.  Situated  thus  in 
the  orbit,  the  eyes  may  be  moved  to  the  extent  of  about  forty- 
five  degrees ;  but  beyond  this  it  is  necessary  to  move  the  head. 

The  accuracy  of  vision  depends  primarily  upon  the  forma- 
tion of  a  perfect  image  upon  the  retina,  which  is  a  membrane, 
sensitive  to  light,  connected  with  the  optic  nerve.  That  such 
an  image  is  actually  formed  has  been  demonstrated  by  an  in- 
strument, the  ophthalmoscope,  which  enables  us  to  look  into 
the  eye  and  see  the  image  itself.  Although  the  image  is  in- 
verted, the  brain  takes  no  cognizance  of  this,  and  every  object 
is  appreciated  in  its  actual  position.  The  image  is  formed  in 
the  eye  in  the  way  in  which  an  image  is  produced  and  thrown 
on  a  screen  by  a  magic  lantern. 

When  a  ray  of  light  passes  obliquely  from  the  air  through 
glass,  water,  or  other  transparent  media,  it  is  bent,  or  refracted, 
and  the  angle  at  which  it  is  bent  is  called  the  index  of  refrac- 
tion. In  passing  to  the  retina,  the  rays  of  light  pass  through 
the  cornea,  a  watery  liquid  (the  aqueous  humor)  surrounding 
the  lens,  the  crystalline  lens,  and  a  gelatinous  liquid  (the  vitre- 
ous humor)  filling  the  posterior  two-thirds  of  the  globe,  all  of 
which  have  the  same  index  of  refraction.  This  provides  that  a 
ray  of  light,  having  once  passed  through  the  cornea,  is  not  re- 
fracted in  passing  through  the  other  transparent  media,  except 
by  the  curvatures  of  the  crystalline,  which  is  a  double-convex 
lens  situated  just  behind  the  pupil.  The  rays  of  light  are  not 
reflected  within  the  eye  itself,  for  the  opaque  parts  of  the  globe 
are  lined  with  a  black  membrane  (the  choroid),  as  the  tube  of 
a  microscope  is  blackened  for  a  similar  purpose.  Practically, 
the  bending  of  the  rays  of  light  is  produced  by  the  curved  sur- 
face of  the  cornea  and  the  two  curved  surfaces  of  the  double- 
convex  crystalline  lens.  These  three  curved  surfaces  bring  the 
rays  from  an  object  to  a  focus  exactly  at  the  retina  in  a  normal 


LIGHT  AND  ITS    USflti  131 

eye.  When,  however,  the  eye  is  too  long,  the  focus  is  in  front 
of  the  retina  unless,  in  near  vision,  the  object  be  brought  very 
near  the  eye,  and  the  person  is  near-sighted.  For  ordinary 
vision,  such  persons  must  wear  properly  adjusted  concave 
glasses  to  carry  the  focus  farther  back.  When  the  eye  is  too 
short,  the  focus  is  behind  the  retina,  and  the  person  is  far- 
sighted  and  must  wear  convex  glasses.  The  first  condition  is 
called  myopia,  and  the  second,  hypermetropia ;  but  in  most 
persons  who  are  obliged  to  wear  convex  glasses  in  advanced 
life,  the  crystalline  lens  has  become  flattened  and  inelastic,  the 
diameter  of  the  eye  being  unaltered.  This  condition  is  called 
presbyopia,  which  means  a  defect  in  vision  due  to  old  age. 

One  of  the  wonderful  things  about  the  eye  is  the  mechanism 
by  which  a  perfect  image  is  formed.  What  is  called  the  area 
of  distinct  vision  is  a  depression  in  the  yellow  spot  of  the  retina, 
which  is  probably  not  more  than  a  thirty-sixth  of  an  inch  in 
diameter.  It  is  with  this  little  spot  that  we  examine  minute 
details  of  objects.  If  we  receive  the  rays  of  light  from  an 
object  upon  a  double-convex  lens  and  throw  them  upon  a  screen 
in  a  darkened  room,  the  image  of  the  object  appears  upon  the 
screen ;  but  in  order  to  render  this  image  even  moderately  dis- 
inct  it  is  necessary  to  carefully  adjust  the  lens,  or  the  combi- 
nation of  lenses,  to  a  certain  distance,  which  is  different  for 
lenses  of  different  curvatures.  In  the  human  eye  the  adjust- 
ment is  most  accurately  made,  almost  instantaneously,  for  any 
desired  distance,  not  by  changing  the  distance  between  the 
crystalline  lens  and  the  retina,  but  by  changing  the  curvature 
of  the  crystalline  lens  itself.  The  way  in  which  this  is  done 
has  been  known  only  within  the  last  few  years.  The  lens  is 
elastic,  and  in  a  quiescent  or  what  is  called  an  indolent  condi- 
tion, is  compressed  between  the  two  layers  of  the  ligament 
which  holds  it  in  place.  In  this  condition,  when  the  rays  from 
distant  objects  are  practically  parallel  as  they  strike  the  eye, 
the  lens  is  adjusted  for  infinite  distance.  When,  however,  we 
examine  a  near  object,  by  the  action  of  a  little  muscle  within 
the  eyeball  the  ligament  is  relaxed  and  the  elastic  lens  becomes 
more  convex.  This  action  is  called  accommodation,  and  is  vol- 
untary, though  usually  automatic.  The  fact  that  it  is  voluntary 


132 


ACHIEVEMENTS  IN  SCIENCE 


is  illustrated  by  the  very  simple  experiment  of  looking  at  a  dis- 
tant object  through  a  gauze  placed  a  few  feet  from  the  eye. 
When  we  see  the  distant  object  distinctly,  we  do  not  see  the 
gauze ;  but  by  an  effort  we  can  distinctly  see  the  meshes  of  the 
gauze,  and  then  the  object  becomes  indistinct.  In  some  old 
persons  the  lens  not  only  becomes  flattened,  but  it  loses  a  great 
part  of  its  elasticity  and  the  power  of  accommodation  is  nearly 
lost. 

The  changes  in  the  curvatures  of  the  lens  in  accommodation 
have  been  actually  measured.  The  lens  itself  is  only  about  a 
third  of  an  inch  in  diameter  and  its  central  portion  is  only  a 
fourth  of  an  inch  thick.  Adjusted  for  infinite  distance,  the 
front  curvature  has  a  radius  of  about  four-tenths  of  an  inch, 
while  for  near  objects  the  radius  is  only  about  three-tenths  of 
an  inch.  A  curious  experiment  is  looking  at  a  minute  object 
through  a  pinhole  in  a  bit  of  paper  or  cardboard,  when  the  ob- 
ject appears  highly  magnified.  This  is  because  the  nearer  the 
object  is  to  the  eye,  the  larger  it  appears.  The  shortest  normal 
distance  of  distinct  vision  is  about  five  inches ;  but  in  looking 
through  a  pinhole  we  can  see  at  a  distance  of  less  than  an  inch, 
using  a  very  small  part  of  the  central  portion  of  the  crystalline 
lens.  Accommodation  for  very  near  objects  is  assisted,  also, 
by  'contraction  of  a  little  band  of  fibers  in  the  iris,  about  a 
fiftieth  of  an  inch  in  width,  immediately  surrounding  the 
pupil. 

The  most  wonderful  thing  about  the  formation  of  a  perfect 
image  upon  the  retina  is  the  mechanism  of  correction  for  form 
and  color.  In  grinding  lenses  for  the  microscope,  for  example, 
it  is  mechanically  easy  to  make  a  very  small  convex  lens  with 
perfectly  regular  curvatures — that  is,  each  curvature  being  a 
portion  of  a  perfect  sphere ;  but  in  such  a  lens  the  focus  of  the 
central  portion  is  longer  than  that  of  the  parts  near  the  edge ; 
and  when  an  object  is  in  focus  for  the  center  it  is  out  of  focus 
for  the  periphery.  This  is  a  fatal  objection  to  the  use  of  un- 
corrected  lenses  of  high  power ;  but  in  microscopes  it  is  cor- 
rected by  combinations  of  lenses,  reducing  the  magnifying 
power,  however,  about  one-half.  This  is  not  all.  When  white 
light  passes  through  a  simple  lens  it  is  decomposed  into  the 


LIGHT  AND  ITS   USES  133 

colors  of  the  spectrum.  This  is  called  dispersion,  and  it  sur- 
rounds the  object  with  a  fringe  of  colors.  The  dispersion  by 
concave  lenses  is  exactly  the  opposite  of  the  dispersion  by  con- 
vex lenses,  so  that  this  may  be  corrected  by  a  combination  of 
the  two ;  but  when  this  is  done  with  lenses  made  of  precisely 
the  same  material,  the  magnifying-  power  is  lost.  Newton  sup- 
posed that  it  was  an  impossibility  to  construct  a  lens  corrected 
for  color  which  would  magnify  objects ;  but  since  the  discovery 
(in  1753  and  1757)  of  different  kinds  of  glass  having  the  same 
refractive  power  but  widely  different  dispersive  powers,  perfect 
lenses  have  been  possible. 

In  the  human  eye,  a  practically  perfect  image,  with  no 
alteration  in  color,  is  produced  by  a  mechanism  which  human 
ingenuity  cannot  imitate.  There  is  a  slight  error  in  the  cornea, 
which  is  corrected  by  an  opposite  error  in  the  crystalline  lens ; 
the  iris  plays  the  part  of  the  diaphragm  of  optical  instruments 
and  shuts  off  the  light  from  the  borders  of  the  crystalline  lens, 
where  the  error  is  greatest,  particularly  in  near  vision;  the 
curvatures  of  the  lens  are  not  perfectly  spherical,  but  are  such 
that  the  form  of  objects  is  not  distorted;  and  while  such  curva- 
tures are  theoretically  calculable,  their  construction  is  practi- 
cally impossible,  as  experience  has  shown ;  different  layers  of 
the  crystalline  lens  have  different  dispersive  powers ;  and  thus 
a  practically  perfect  image,  with  no  appreciable  decomposition 
of  white  light,  is  formed  on  the  retina. 

Another  wonderful  thing  about  the  eye,  which  adapts  it 
most  beautifully  to  our  requirements,  is  the  division  of  the  sen- 
sitive parts  of  the  retina  into  a  very  small  area  for  distinct 
vision,  which  we  use  for  reading,  for  example,  and  a  large  sur- 
rounding area  in  which  vision  is  indistinct.  If  we  saw  with 
equal  distinctness  with  all  parts  of  the  retina,  the  vision  of 
minute  objects  would  be  confused  and  imperfect.  As  it  is,  the 
area  of  distinct  vision  is  very  small,  probably  less  than  one 
thirty-sixth  of  an  inch  in  diameter.  In  this  area,  the  distance 
between  the  separate  sensitive  elements  is  not  more  than  one 
thirty-five-hundredth  of  an  inch;  while,  if  we  pass  from  this 
only  eight  degrees,  the  distance  is  increased  a  hundred  times. 
Still,  in  looking  at  any  one  object  in  the  center  of  distinct 


134  ACHIEVEMENTS  IN  SCIENCE 

vision,  the  imperfect  forms  of  surrounding  objects  are  appreci- 
ated, warning  us,  perhaps,  of  the  approach  of  danger. 

The  mechanism  of  distinct  and  indistinct  vision  has  been 
understood  only  since  1876.  The  sensitive  parts  of  the  retina 
are  little  rods  and  cones  forming  a  layer  by  themselves.  In 
1876,  Boll  discovered  that  in  frogs  kept  in  the  dark  the  rods  of 
the  retina  were  colored  a  dark  purple ;  but  on  exposure  to  light 
the  color  faded,  becoming  first  yellow  and  then  white.  Since 
that  time,  physiologists  have  been  carefully  investigating  visual 
purple  and  visual  yellow.  Just  outside  the  layer  of  rods  and 
cones  are  the  dark  cells  which  render  the  greatest  part  of  the 
interior  of  the  eye  almost  black.  In  the  dark,  these  cells  send 
little  filaments  between  the  rods  and  discharge  a  liquid  which 
colors  the  rods  alone.  When  the  rods  are  thus  colored,  the 
eye  is  extremely  sensitive,  so  that  a  bright  light  is  dazzling  and 
painful  and  obscures  distinct  vision.  This  is  the  reason  why 
we  cannot  see  distinctly  when  we  come  suddenly  from  the  dark 
into  a  full  light.  In  a  few  seconds,  however,  the  color  is 
bleached  to  a  yellow  and  the  difficulty  passes  away.  When,  on 
the  other  hand,  we  pass  from  a  bright  light  into  the  dark,  the 
retina  has  lost  its  sensibility  from  disappearance  of  the  visual 
purple,  and  we  cannot  see  at  all  until  the  purple  is  reproduced, 
as  it  is  in  the  absence  of  light.  This  difference  is  not  due  to 
dilatation  of  the  pupil  in  the  dark  and  contraction  under  the  in- 
fluence of  light,  as  is  popularly  supposed,  for  a  person  does  not 
see  better  in  the  dark  when  the  pupil  has  been  fully  dilated  by 
belladonna. 

In  the  little  area  of  distinct  vision  there  is  never  any  visual 
purple.  This  area  we  always  use  with  sufficient  light  for 
minute  details  of  objects,  making  then  the  greatest  use  of  the 
mechanism  of  accommodation.  The  area  outside  of  this  is  used 
for  indistinct  vision,  and  as  the  color  is  then  yellow  instead  of 
purple,  it  is  only  moderately  sensitive.  To  express  the  condi- 
tions in  a  few  words,  the  minute  area  for  distinct  vision  is  used 
by  day,  and  the  area  for  indistinct  vision,  with  its  visual  purple, 
is  used  by  night. 

A  very  curious  condition  is  what  is  known  as  night-blind- 
ness. Sometimes,  in  long  tropical  voyages,  sailors  become 


LIGHT  AND  ITS   USES  135 

affected  with  total  blindness  at  night,  while  vision  in  the  day- 
time is  perfect.  The  glare  of  the  sun  in  the  long  days  bleaches 
the  visual  purple  so  completely  that  it  cannot  be  restored  in  a 
single  night,  and  the  area  of  indistinct  vision  becomes  insensi- 
ble. This  trouble  is  purely  local  and  is  remedied  by  rest  of  the 
eye.  If  one  eye  be  protected  by  a  bandage  during  the  day,  this 
eye  will  be  restored  sufficiently  for  the  next  night's  watch, 
while  the  unprotected  eye  is  as  bad  as  ever.  Snow-blindness 
in  the  arctic  regions  is  due  to  the  same  cause. 

We  receive  the  impression  of  a  single  object,  although  there 
are  two  images — one  in  either  eye ;  but  it  is  necessary  that  the 
images  be  made  upon  corresponding  points  in  the  two  retinae. 
If  the  angle  of  vision  in  one  eye  be  deviated  even  to  a  slight 
degree  by  pressing  on  one  globe  with  the  ringer,  we  see  two 
images.  One  can  appreciate  how  exactly  these  points  must 
correspond  when  it  is  remembered  that  two  rays  of  light  ap- 
pear as  one  only  when  the  distance  between  them  is  one  thirty- 
five-hundredth  of  an  inch. 

In  either  eye  there  is  a  blind  spot,  and  this  is  at  the  point 
of  penetration  of  the  optic  nerve ;  but,  inasmuch  as  this  spot  is 
in  the  area  of  indistinct  vision,  and  is  so  situated — a  little  within 
the  line  of  distinct  vision — that  an  impression  is  never  made 
on  both  blind  spots  by  the  same  object,  this  blindness  is  never 
appreciable,  and  the  spot  can  be  detected  only  by  the  most 
careful  investigation. 

Not  the  least  of  the  wonders  of  the  eye  are  connected  with 
the  appreciation  of  images  made  upon  the  retina  by  certain 
parts  of  the  brain.  It  is  literally  true  that  a  person  may  see 
and  yet  not  perceive.  It  has  happened,  in  certain  injuries  of 
the  brain,  that  a  person  sees  and  reads  the  words  in  a  book 
and  yet  does  not  perceive  their  significance.  This  is  called 
word-blindness.  In  a  certain  portion  of  the  brain  is  a  part 
which  enables  us  to  recognize  the  fact  that  we  see  an  object; 
yet  this  object  conveys  no  idea.  There  are  two  of  these  so- 
called  centers  of  vision,  one  on  either  side,  and  their  action  is 
partly  crossed.  When  the  center  is  destroyed  on  one  side,  the 
inner  half  of  one  eye  and  the  outer  half  of  the  other  eye  are 
blinded.  Farther  back  in  the  brain,  however,  is  a  center  which 


136  ACHIEVEMENTS  IN  SCIENCE 

enables  us  to  perceive  or  understand  what  is  seen.  When  this 
center  is  destroyed  we  see  objects  and  may  avoid  obstacles  in 
walking,  but  persons,  words,  etc.,  are  not  recognized.  This 
center  exists  only  on  the  left  side  of  the  brain. 

An  impression,  however  short,  made  upon  the  retina  is  per- 
ceived. The  letters  on  a  printed  page  are  distinctly  seen  when 
illuminated  by  an  electric  spark,  the  duration  of  which  is  only 
forty  billionths  of  a  second ;  but  the  impression  remains  much 
longer.  Anything  in  motion  appears  to  us  in  a  way  quite  dif- 
ferent from  the  single  impression  that  we  should  have  from  an 
electric  spark.  In  a  picture  representing  an  animal  in  motion, 
as  it  appears  in  an  instantaneous  photograph,  the  positions 
seem  absurd  and  like  nothing  we  have  ever  seen.  In  looking 
at  a  horse  in  action,  the  impressions  made  by  the  different  posi- 
tions of  the  animal  run  into  each  other,  and  art  should  represent 
as  nearly  as  possible  the  sum  or  average  of  these  impressions. 
It  is  also  true  that  impressions  are  diffused  in  the  retina  beyond 
the  points  upon  which  they  are  directly  received.  This  is  called 
irradiation ;  and  the  impression  is  diffused  farther  for  white  or 
light-colored  than  for  black  or  dark  objects.  It  is  well  known 
that  a  white  square  looks  considerably  larger  than  a  dark 
square  of  exactly  the  same  size ;  or  the  hands  in  white  gloves 
look  larger  than  in  black  gloves. 

I  have  described,  in  as  simple  a  way  as  possible,  some  won- 
derful things  about  the  eye  ascertained  and  explained  by  modern 
investigations ;  but  there  are  many  interesting  facts  ascertained 
which  space  has  not  permitted  me  to  discuss,  and  there  still 
remains  much  that  is  not  yet  understood.  The  whole  question 
of  the  appreciation  of  colors  and  of  color  blindness  is  still 
wrapped  in  mystery.  We  know  that  some  persons  cannot  dis- 
tinguish between  certain  colors,  but  the  reason  of  this  is  ob- 
scure. Perfect  sight  can  exist  only  when  the  eye  is  perfect. 
The  form  and  color  of  objects  may  be  distorted  so  that  an  inac- 
curate image  is  formed  upon  the  retina,  and  this  image,  how- 
ever imperfect  it  may  be,  is  what  is  perceived  by  the  brain. 
In  hearing,  the  case  is  different.  The  waves  of  sound,  if  they 
be  conducted  to  the  internal  ear,  and  if  the  nerve  of  hearing, 
with  its  terminations,  be  normal,  cannot  be  modified  in  course 


LIGHT  AND  ITS    USES 


137 


of  transmission.  Sounds  are  always  appreciated  at  their  exact 
value,  except  as  regards  intensity.  Enough  has  been  said 
about  the  eye,  I  think,  to  show  that  it  is  perfectly  adapted  to 
all  requirements,  and  whatever  defects  it  may  seem  to  have, 
viewed  as  an  optical  instrument,  render  it  more  useful  to  us 
than  if  these  apparent  defects  did  not  exist. 


ASTRONOMY 
Discoveries  in  the  Heavens 

By  ALFRED  RUSSEL  WALLACE 

MANY  of  the  most  striking  discoveries  in  this  science  have 
been  already  described  under  Spectrum  Analysis ;  but 
there  remain  a  few  great  advances,  due  either  to  observation  or 
to  theory,  which  are  of  sufficient  popular  interest  to  demand 
notice  in  any  sketch,  however  brief,  of  the  scientific  progress 
of  the  century. 

With  the  single  exception  of  Uranus,  discovered  by  Herschel 
in  1781,  no  addition  had  been  made  to  the  five  planets  known 
to  the  ancients  till  the  commencement  of  the  present  century, 
when  Ceres,  the  first  of  the  minor  planets,  was  discovered  in 
1801,  and  three  others  between  that  date  and  1807.  No  more 
were  found  till  one  was  added  in  1845,  and  another  in  1847. 
Since  that  time  no  year  has  passed  without  the  detection  of 
one  or  more  new  planets  belonging  to  the  same  system,  till  in 
September,  1896,  their  number  amounted  to  417.  These  small 
bodies  form  a  kind  of  planetary  ring  situated  between  Mars 
and  Jupiter,  where  it  had  long  been  suspected  a  planet  ought 
to  be  found,  because  the  distance  between  these  older  planets 
was  so  great  as  to  be  quite  out  of  proportion  with  the  regular 
increase  of  distance  maintained  by  the  other  members  of  the 
system.  It  was  at  first  thought  that  these  asteroids  or  mine 
planets  were  the  shattered  remains  of  a  much  larger  one ;  but 
more  extended  knowledge  of  the  constitution  of  the  solar  sys- 
tem renders  it  more  probable  that  they  really  constitute  a 
of  matter  thrown  off  by  the  sun  during  its  progressive  contrac- 
tion ;  and  that  some  peculiar  conditions  have  prevented  its  vari- 

138 


ASTRONOMY  139 

ous  parts  from  aggregating  into  a  single  planet.  This  is  ren- 
dered more  probable  by  two  other  remarkable  discoveries  relat- 
ing to  meteors  and  comets,  and  to  Saturn's  rings,  which  will  be 
discussed  later  on. 

The  next  large  planet  added  to  our  system  is  especially  in- 
teresting, as  affording  a  striking  demonstration  of  the  theory  of 
gravitation,  and  a  no  less  striking  example  of  the  powers  of 
modern  mathematics.  It  had  been  found  that  the  motions  of 
Uranus  were  not  exactly  what  they  ought  to  be,  if  due  solely 
to  the  attraction  of  the  sun  and  the  disturbing  influence  of 
Jupiter  and  Saturn,  and  it  was  thought  possible  that  there 
might  be  another  planet  beyond  it  to  cause  these  irregularities, 
In  the  year  1843  a  young  Cambridge  student  (John  Couch 
Adams)  of  the  highest  mathematical  ability,  determined  to  see 
whether  it  was  not  possible  to  prove  the  existence  of  such  a 
planet;  and  having  taken  his  degree  as  senior  wrangler,  he 
at  once  devoted  himself  to  the  work,  and  after  two  years  of 
study  and  calculation  he  was  able  to  declare  that  a  planet  which 
would  account  for  the  perturbation  of  Uranus  must,  if  it  ex- 
isted, be  at  that  time  in  a  certain  part  of  the  heavens,  and  he 
sent  his  paper  on  the  subject  to  the  Astronomer-Royal  in  Octo- 
ber, 1845.  By  an  extraordinary  coincidence,  a  French  astrono- 
mer (Leverrier)  had  been  for  some  years  working  out  the 
motions  of  the  various  planets,  and  in  doing  so  had  also  reached 
the  conclusion  that  there  must  be  another  unknown  body  to 
produce  the  perturbations  of  Uranus,  which  were  at  that  time 
unusually  large.  His  calculations  and  results  were  published 
at  Paris  in  November,  1845,  and  June,  1846,  and  he  gave  a 
position  for  the  unknown  planet  differing  only  one  degree  from 
that  given  by  Adams.  On  reading  these  papers,  and  seeing 
the  agreement  of  two  independent  workers,  the  Astronomer- 
Royal  asked  Professor  Challis,  of  the  Cambridge  Observatory, 
to  search  for  the  planet,  and  on  doing  so  he  actually  observed 
it  on  August  4th,  and  again  on  August  I2th;  but  having  no 
accurate  chart  of  that  part  of  the  heavens  he  could  not  be  sure 
that  it  was  not  a  small  star.  A  month  later  it  was  found  and 
identified  at  Berlin,  from  information  furnished  by  Leverrier 
It  thus  appears  that  Adams  first  privately  announced  the  posi- 


140  ACHIEVEMENTS  IF  SCIENCE 

tion  of  the  new  planet,  and  that  it  was  first  observed  at  Cam- 
bridge ;  while  the  somewhat  later  announcement  by  Leverrier 
and  discovery  at  Berlin  were  made  public,  and  thus  gained  the 
honors  of  priority.  The  two  discoveries  were,  however,  practi- 
cally simultaneous  and  independent,  and  the  names  of  Adams 
and  Leverrier  should  forever  be  jointly  associated  with  the 
planet  Neptune. 

Other  important  discoveries  in  the  planetary  system  are  due 
to  the  increased  power  of  modern  telescopes  and  the  greater 
number  of  observers.  In  1877  two  minute  satellites  of  Mars 
were  discovered  at  Washington,  by  means  of  the  large  tele- 
scope with  a  25-inch  object  glass,  then  the  largest  in  the  world. 
These  are  remarkable  in  being  exceedingly  small,  and  very  close 
to  the  planet.  They  are  said  to  be  only  six  or  seven  miles  in 
diameter,  and  the  inner  one  is  only  about  5,800  miles  from  the 
center,  or  3,800  from  the  surface,  of  the  planet,  around  which 
it  revolves  in  less  than  eight  hours ;  while  the  outer  one  is 
about  14,500  miles  away,  and  revolves  in  a  little  more  than 
thirty  hours.* 

Still  more  recently  (in  September,  1892),  a  fifth  satellite  of 
Jupiter  was  discovered  by  means  of  the  great  Lick  telescope  in 
California.  This  also  is  very  small  and  very  close  to  the  planet, 
being  less  than  half  the  diameter,  or  about  40,000  miles,  from 
its  surface. 

Another  very  remarkable  discovery  is  that  of  a  system  of 
symmetrical  markings,  covering  a  large  part  of  the  surface  of 
Mars.  They  consist  of  a  series  of  triangles  or  quadrilaterals 
bounded  by  straight  lines,  which  are  sometimes  seen  double,  at 
other  times  single,  or  are  even  altogether  invisible.  Another 
peculiar  feature  is,  that  where  these  canals  (as  they  are  termed) 
intersect  there  is  always  a  black  circular  spot,  very  distinct, 
and  unlike  any  markings  upon  other  parts  of  the  surface.  It  is 


*In  "Gulliver's  Travels,"  published  in  1726,  Swift  describes  the  astronomers 
of  Laputa  as  having  "  discovered  two  lesser  stars,  or  satellities,  which  revolve 
around  Mars ;  whereof  the  innermost  is  distant  from  the  center  of  the  primary 
planet  exactly  three  of  his  diameters,  and  the  outermost  five  ;  the  former  revolves 
in  the  space  of  ten  hours,  and  the  latter  in  twenty-one  and  a  half."  This  is  a 
wonderful  anticipation,  especially  as  to  time  of  revolution,  and  if  we  substitute 
"  radii  "  for  "diameters,"  the  distances  are  also  very  near. 


ASTRONOMY  141 

a  curious  fact  that  the  double  canals  sometimes  enclose  a  space 
of  more  than  a  hundred  miles  wide  and  several  hundred  long, 
adding  to  the  appearance  of  artificiality.  Sometimes  no  canals 
are  seen,  but  they  come  into  view  as  the  polar  snows  begin  to 
melt ;  hence  the  suggestion  that  they  really  indicate  great  canals 
to  carry  off  the  water  from  the  rapidly  melting  snow  and  dis- 
tribute it  by  irrigation  channels  over  the  adjacent  land,  which, 
being  rapidly  covered  with  vegetation,  causes  the  change  of 
color  which  renders  them  visible.  These  observations  were 
made  by  Mr.  Percival  Lowell  during  the  favorable  opposition, 
in  1894,  at  his  observatory  in  Arizona,  where  the  exceptional 
purity  of  the  atmosphere  renders  it  possible  almost  constantly 
to  observe  details  which  are  elsewhere  rarely  visible.  If  future 
observations  should  confirm  the  views  as  to  the  artificial  nature 
of  these  features  of  the  surface  of  the  planet  which  most  nearly 
resembles  our  earth,  it  must  be  considered  to  be  the  most  sen- 
sational astronomical  discovery  of  the  nineteenth  century,  and 
that  which  opens  up  the  most  exciting  possibilities  as  to  com- 
munication with  beings  who  are  sufficiently  advanced  to  execute 
such  widespread  and  gigantic  irrigation  works. 

The  ring  around  the  planet  Saturn  was  long  supposed  to 
be  single,  and  to  be  solid  like  the  planet  itself;  but  with  im- 
proved telescopes  it  was  found  to  be  double,  and  with  still  finer 
instruments  to  consist  of  an  indefinite  number  of  rings  close 
together,  one  of  them  being  very  obscure,  as  if  formed  of  nebu- 
lous matter.  In  the  year  1859,  Clerk-Maxwell,  by  a  profound 
mathematical  investigation,  proved  that  either  solid  or  liquid 
rings  would  be  unstable,  and  would  inevitably  break  up  so  as 
to  form  a  number  of  satellites ;  and  he  concluded  that  the  rings 
really  consisted  of  a  crowd  of  small  bodies  so  near  together  as 
to  appear  like  a  solid  mass ;  and  as  the  appearance  of  the  rings, 
and  some  slight  changes  detected  in  them,  were  in  harmony 
with  this  view,  it  has  been  generally  accepted.  But  quite  re- 
cently the  wonderful  instrument,  the  spectroscope,  has  given 
the  final  demonstration  that  this  theory  is  correct.  If  the  rings 
are  solid,  it  is  clear  that  a  point  on  the  outer  edge  must  move 
more  rapidly  than  one  on  the  inner  edge ;  whereas,  if  they  con- 
sist of  separate  particles,  each  revolving  independently  round 


142  ACHIEVEMENTS  IN  SCIENCE 

the  planet,  then,  in  accordance  with  the  laws  of  all  planetary 
motions,  those  forming  the  inner  side  of  the  rings,  being  nearer 
to  the  planet,  must  move  much  quicker  than  those  on  the  outer 
side.  As  already  explained,  the  spectroscope  enables  us  to 
measure  motion  in  the  line  of  sight — that  is,  toward  or  away 
from  us — of  any  heavenly  bodies,  and  by  observing  the  outer 
extremities  of  the  rings  to  the  right  and  left  of  the  planet, 
where  the  motion  is,  of  course,  in  these  two  directions,  it  is 
found  that  the  motion  of  the  inner  edge  is  considerably  more 
rapid  than  that  of  the  outer  edge,  showing  that  those  parts 
move  round  the  planet  independently,  and  are  therefore  formed 
of  separate  particles  or  small  masses.  These  observations 
were  made  by  the  American  astronomer,  Professor  James  E. 
Keller,  in  1895,  and  are  of  extreme  delicacy;  but  that  they  are 
trustworthy  is  shown  by  the  fact  that  the  resulting  velocities 
are  in  accordance  with  Kepler's  third  law,  which  determines 
the  relative  motions  of  all  planetary  bodies  at  varying  distances 
from  the  primary. 

A  still  more  important  discovery  is  that  which  has  ex- 
plained, by  one  consistent  theory,  the  various  phenomena  pre- 
sented by  aerolites,  fireballs,  and  shooting  or  falling  stars,  now 
generally  classed  as  meteors  and  meteorites ;  and  this  theory 
is  found  to  have  an  important  bearing  on  the  constitution  of 
the  solar  system,  and  perhaps  even  on  that  of  the  whole  stellar 
universe.  Although  there  are  records  of  the  fall  of  solid  stones 
from  the  sky  in  the  works  of  classical,  Chinese,  and  European 
authors,  from  654  B.  c.  down  to  our  times,  while  the  astronomer 
Gassendi  himself  witnessed  the  fall  of  a  stone  weighing  fifty- 
nine  pounds  in  the  year  1627,  in  the  south  of  France,  yet  the 
phenomenon  was  so  rare,  and  so  inexplicable,  that  it  was  often 
disbelieved.  One  philosopher  is  reported  to  have  disposed  of 
the  whole  matter  by  saying,  "  There  are  no  stones  in  the  sky, 
therefore  none  can  fall  from  it."  But  the  evidence  for  such 
falls  soon  became  overwhelming,  and  their  connection  with 
fireballs  and  shooting  stars  was  also  well  established.  One  of 
the  most  remarkable  of  modern  meteors  was  that  seen  at  Aigle 
in  Normandy,  on  April  26, 1803.  About  I  P.M.  a  brilliant  fire- 
ball was  seen  traversing  the  air  at  great  speed.  A  violent  ex- 


RICHARD  ANTHONY   PROCTOR. 


ASTRONOMY  143 

plosion  followed,  apparently  proceeding  from  a  small  lofty 
cloud.  This  was  no  doubt  the  product  of  the  explosion  which 
would  be  visible  long  before  the  sound  was  heard,  and  then 
came  a  perfect  shower  of  stones,  nearly  three  thousand  being 
picked  up,  the  largest  weighing  eight  pounds.  A  still  more 
extraordinary  meteor  was  seen  on  March  19,  1719,  about  eight 
o'clock  in  the  evening,  in  all  parts  of  England,  Scotland,  and 
Ireland.  In  London  it  appeared  like  a  ball  of  fire  as  large  as 
the  moon ;  at  Exeter  the  light  was  like  that  of  the  sun.  It  was 
followed  by  a  broad  stream  of  light,  and  burst  with  a  report 
like  that  of  a  cannon,  with  a  great  display  of  red  sparks  like  a 
huge  sky-rocket;  but  as  it  was  then  over  the  sea,  between 
Devonshire  and  the  coast  of  Brittany,  its  fragments  were  not  re- 
coverable. Dr.  Whiston,  Newton's  successor  as  professor  of 
mathematics  at  Cambridge,  who  published  an  account  of  it, 
calculated  its  height  over  London  as  fifty-one  miles,  and  over 
Devonshire  thirty-nine  miles. 


ASTRONOMY 
The  Planet  Mars 

By  SIR  ROBERT  BALL* 

QEEING  that  the  existence  of  intelligence  is  a  characteristic 
O  feature  of  this  earth,  we  feel  naturally  very  much  inter- 
ested in  the  question  as  to  whether  there  can  be  intelligent 
beings  dwelling  on  other  worlds  around  us.  It  is  only  regret- 
table that  our  means  of  solving  this  problem  are  so  inadequate. 
Indeed,  until  quite  lately  it  would  have  been  almost  futile  to 
discuss  this  question  at  all.  All  that  could  then  have  been 
said  on  the  subject  amounted  to  little  more  than  the  statement 
that  it  would  be  intolerable  presumption  for  man  to  suppose 
that  he  alone,  of  all  beings  in  the  universe,  was  endowed  with 
intelligence,  and  that  his  insignificant  little  earth,  alone  amid 
the  myriad  globes  of  space,  enjoyed  the  distinction  of  being 
the  abode  of  life.  Recent  discovery  has,  however,  given  a  new 
aspect  to  this  question.  At  the  end  of  the  century  certain 
observations  were  made  disclosing  features  in  the  neighboring 
planet,  Mars,  which  have  riveted  the  attention  of  the  world. 
On  this  question,  above  most  others,  extreme  caution  is  neces- 
sary. It  is  especially  the  duty  of  the  man  of  science  to  weigh 
carefully  the  evidence  offered  to  him  on  a  subject  so  important. 
He  will  test  that  evidence  by  every  means  in  his  power,  and  if 
he  finds  the  evidence  establishes  certain  conclusions,  then  he 
is  bound  to  accept  such  conclusions  irrespective  of  all  other 
circumstances. 

Mr.  Percival  Lowell  has  an  observatory  in  an  eminently  fa- 


*  Professor  of  Astronomy,  Cambridge  University,  England. 

144 


ASTRONOMY  145 

vorable  position  at  Flagstaff,  in  Arizona.  He  has  a  superb 
telescope,  and  enjoys  a  perfect  climate  for  astronomical  work. 
Aided  by  skilful  assistants,  he  has  observed  Mars  under  the 
most  favorable  circumstances  with  great  care  for  some  years. 
I  must  be  permitted  to  say  that,  having  carefully  studied  what 
Mr.  Lowell  has  set  forth,  and  having  tested  his  facts  arid 
figures  in  every  way  in  my  power,  most  astronomers  have  come 
to  the  conclusion  that,  however  astonishing  his  observations 
may  seem  to  be,  we  cannot  refuse  to  accept  them. 

No  one  has  ever  seen  inhabitants  on  Mars,  but  Mr.  Percival 
Lowell  and  one  or  two  other  equally  favored  observers  have 
seen  features  on  that  planet  which,  so  far  as  our  experience 
goes,  can  be  explained  in  no  other  way  than  by  supposing  that 
they  were  made  by  an  intelligent  designer  for  an  intelligent 
purpose.  Mr.  Lowell  has  discovered  that  there  are  certain 
operations  in  progress  on  the  surface  of  Mars  which,  if  met 
with  on  this  earth,  we  should  certainly  conclude,  without  the 
slightest  hesitation,  were  the  result  of  operations  conducted 
under  what  we  consider  rational  guidance. 

A  river,  as  Nature  has  made  it,  wends  its  way  to  and  fro ; 
it  never  takes  the  shortest  route  from  one  point  to  another ; 
the  width  of  the  river  is  incessantly  changing ;  sometimes  it 
expands  into  a  lake,  sometimes  it  divides  so  as  to  inclose  an 
island.  If  we  could  discern  through  our  telescopes  a  winding 
line  such  as  I  have  described  on  Mars  it  might  perhaps  repre- 
sent a  river. 

But  suppose,  instead  of  a  winding  line,  there  was  a  per- 
fectly straight  line,  or  rather  a  great  circle  on  the  globe  drawn 
as  straight  as  a  surveyor  could  lay  it  out — if  we  beheld  an 
object  like  that  on  Mars  I  think  we  should  certainly  infer  that 
it  was  not  a  river  made  in  the  ordinary  course  of  natural  opera- 
tions ;  no  natural  river  ever  runs  in  that  regular  fashion.  If 
such  a  straight  line  were  indeed  a  river,  then  it  must  have  been 
designedly  straightened  by  human  agency  or  by  some  other 
intelligent  agency  for  some  particular  purpose.  In  its  larger 
features  Nature  does  not  work  by  straight  lines.  A  long  and 
rfectly  straight  object,  if  found  on  our  earth,  might  be  a 
1  or  it  might  be  a  road ;  it  might  be  a  railway  or  a  terrace 
10 


146  ACHIEVEMENTS  IN  SCIENCE 

of  some  kind ;  but  assuredly  no  one  would  expect  it  to  be  a 
natural  object. 

We  have  the  testimony  of  Schiaparelli,  now  strengthened 
by  that  of  Mr.  Lowell  and  his  assistants,  that  there  are  many 
straight  lines  of  this  kind  on  Mars.  They  appear  to  be  just  as 
straight  as  a  railway  would  have  to  be  if  laid  across  the  flat  and 
boundless  prairie,  where  the  engineer  encountered  no  obstacle 
whatever  to  make  him  swerve  from  the  direct  path.  These 
lines  on  Mars  run  for  hundreds  of  miles,  sometimes,  indeed, 
I  should  say  for  thousands  of  miles.  They  are  far  wider  than 
any  terrestrial  river,  except  perhaps  the  Amazon  for  a  short 
part  of  its  course.  The  lines  on  Mars  are  about  forty  miles 
wide.  Indeed,  the  planet  is  so  distant  that  if  these  lines  were 
much  narrower  than  forty  miles  they  would  be  invisble.  Each 
of  them  is  marvelous  in  its  uniformity  throughout  its  entire 
length. 

The  existence  of  these  straight  lines  on  the  planet  contains 
perhaps  the  first  suggestion  of  the  presence  of  some  intelligent 
beings  on  Mars.  The  mere  occurrence  of  a  number  of  per- 
fectly straight,  uniform  lines  on  such  a  globe  would  in  itself  be 
a  sufficiently  remarkable  circumstance.  But  there  are  other 
features  exhibited  by  these  objects  which  also  suggest  the 
astonishing  surmise  that  they  have  been  constructed  by  some 
intelligent  beings  for  some  intelligent  purposes. 

Sometimes  two  of  these  lines  will  start  from  a  certain  junc- 
tion, sometimes  there  will  be  a  third  or  a  fourth  from  the  same 
junction;  in  one  case  there  are  as  many  as  seven  radiating  from 
the  same  point.  Such  an  arrangement  of  these  straight  lines 
is  certainly  unlike  anything  that  we  find  in  Nature.  We  are 
led  to  seek  for  some  other  explanation  of  the  phenomenon,  and 
here  is  the  explanation  which  Mr.  Lowell  offers : 

It  has  recently  been  found  that  there  are  no  oceans  of  water 
on  the  planet  Mars.  In  earlier  days  it  used  no  doubt  to  be  be- 
lieved that  the  dark  marks  easily  seen  in  the  telescope  could 
represent  nothing  but  oceans,  but  I  think  we  must  now  give 
up  the  notion  that  these  are  watery  expanses.  Indeed,  there 
is  not  much  water  on  that  globe  anywhere  in  comparison  with 
the  abundance  of  water  on  our  earth.  It  is  the  scarcity  of 


ASTRONOMY  147 

water  which  seems  to  give  a  clew  to  some  of  the  mysteries  dis- 
covered on  Mars  by  Schiaparelli  and  Lowell. 

As  our  earth  moves  round  the  sun  we  have,  of  course,  the 
changing  seasons  of  the  year.  In  a  somewhat  similar  manner 
Mars  revolves  around  the  sun,  and  accordingly  this  planet  has 
also  its  due  succession  of  seasons.  There  is  a  summer  on 
Mars,  and  there  is  a  winter;  during  the  winter  on  that  globe 
the  poles  of  the  planet  are  much  colder  than  at  other  seasons, 
and  the  water  there  accumulates  in  the  form  of  ice  or  snow  to 
make  those  ice-caps  that  telescopic  observers  have  so  long 
noticed.  In  this  respect  Mars,  of  course,  is  like  our  earth. 
The  ice-cap  at  each  pole  of  our  globe  is  so  vast  that  even  the 
hottest  summer  does  not  suffice  to  melt  the  accumulation; 
much  of  the  ice  and  snow  there  remains  to  form  the  eternal 
snow  which  every  arctic  explorer  so  well  knows.  It  would 
seem,  however,  that  the  contrast  between  winter  and  summer 
on  Mars  must  be  much  more  deeply  marked  than  the  contrast 
between  winter  and  summer  on  our  earth.  During  the  sum- 
mer of  Mars  ice  and  snow  vanish  altogether  from  the  poles  of 
that  planet. 

Mr.  Lowell  supposes  that  water  is  so  scarce  on  Mars  that 
the  inhabitants  have  found  it  necessary  to  economize  to  the 
utmost  whatever  stock  there  may  be  of  this  most  necessary 
element.  The  observations  at  Flagstaff  tend  to  show  that  the 
dark  lines  on  Mars  mark  the  course  of  the  canals  by  which  the 
water  melted  in  summer  in  the  arctic  regions  is  conducted  over 
the  globe  to  the  tracts  where  the  water  is  wanted.  Not  that 
the  line  as  we  see  it  represents  actually  the  water  itself ;  the 
straight  line  so  characteristic  of  Mars's  globe  seems  rather  to 
correspond  to  the  zones  of  vegetation  which  are  brought  into 
culture  by  means  of  water  that  flows  along  a  canal  in  its  center. 
In  much  the  same  way  would  the  course  of  the  Nile  be  exhib- 
ited to  an  inhabitant  on  Mars  who  was  directing  a  telescope 
toward  this  earth :  the  river  itself  would  not  be  visible,  but  the 
cultivated  tracts  which  owe  their  fertility  to  the  irrigation  from 
the  river  would  be  broad  enough  to  be  distinguishable.  The 
appearance  of  these  irrigated  zones  would  vary,  of  course,  with 
the  seasons;  and  we  observe,  as  might  have  been  expected, 


14$  ACHIEVEMENTS  IN  SCIENCE 

changes  in  the  lines  on  Mars  corresponding  to  the  changes  in 
the  seasons  of  the  planet. 

A  noteworthy  development  of  astronomy  in  the  last  cen- 
tury has  been  the  erection  of  mighty  telescopes  for  the  study 
of  the  heavens.  It  must  here  suffice  to  mention,  as  the  latest 
and  most  remarkable  of  these,  the  famous  instrument  at  the 
Yerkes  Observatory,  which  belongs  to  the  University  of  Chi- 
cago. Just  as  the  century  is  drawing  to  its  close,  the  Yerkes 
telescope  has  begun  to  enter  on  its  sublime  task  of  exhibiting 
the  heavens  under  greater  advantages  than  have  ever  been  pre- 
viously afforded  to  any  astronomers  since  the  world  began. 

When  the  University  of  Chicago  was  founded,  it  was  desired 
to  associate  with  the  university  an  astronomical  observatory 
which  should  be  worthy  of  the  astonishing  place  that  this  won- 
derful city  has  assumed  in  the  world's  history.  Mr.  Yerkes,  an 
American  millionaire,  generously  undertook  to  provide  the  cost 
of  this  observatory.  Two  noble  disks  of  glass,  forty  inches  in 
diameter,  were  produced  at  the  furnaces  of  Messrs.  Mantois,  in 
Paris ;  these  disks  were  worked  by  Mr.  Alvan  Clark,  of  Boston, 
into  the  famous  object  glass  which,  weighing  nearly  half  a  ton, 
has  now  been  mounted  in  what  we  may  describe  as  a  temple 
or  a  palace  such  as  had  never  been  dreamed  of  before  in  the 
whole  annals  of  astronomy. 


ASTRONOMY 
The  Starry  Heavens 

By  SIR  ROBERT  BALL 

WE  are  about  to  discuss  one  of  the  grandest  truths  in  the 
whole  of  nature.  We  have  had  occasion  to  see  that 
this  sun  of  ours  is  a  magnificent  globe  immensely  larger  than 
the  greatest  of  his  planets,  while  the  greatest  of  these  planets 
is  immensely  larger  than  this  earth ;  but  now  we  are  to  learn 
that  our  sun  is,  indeed,  only  a  star  not  nearly  so  bright  as  many 
of  those  which  shine  over  our  heads  every  night.  We  are  com- 
paratively close  to  the  sun,  so  that  we  are  able  to  enjoy  his 
beautiful  light  and  cheering  heat.  Each  of  those  other  myriads 
of  stars  is  a  sun,  and  the  splendor  of  those  distant  suns  is  often 
far  greater  than  that  of  our  own.  We  are,  however,  so  enor- 
mously far  from  them  that  they  appear  dwindled  down  to  in- 
significance. To  judge  impartially  between  our  sun  or  star 
ind  such  a  sun  or  star  as  Sirius  we  should  stand  half  way  be- 
tween the  two ;  it  is  impossible  to  make  a  fair  estimate  when 
we  find  ourselves  situated  close  to  one  star  and  a  million  times 
as  far  from  the  other.  After  allowance  is  made  for  the  imper- 
fections of  our  point  of  view,  we  are  enabled  to  realize  the 
majestic  truth  that  the  sun  is  no  more  than  a  star,  and  that  the 
other  stars  are  no  less  than  suns.  This  gives  us  an  imposing 
idea  of  the  extent  and  magnificence  of  the  universe  in  which 
we  are  situated.  Look  up  at  the  sky  at  night — you  will  see  a 
host  of  stars ;  try  to  think  that  every  one  of  them  is  itself  a 
sun.  It  may  probably  be  that  those  suns  have  planets  circling 
round  them,  but  it  is  hopeless  for  us  to  expect  to  see  such 
planets.  Were  you  standing  on  one  of  those  stars  and  looking 

149 


150  ACHIEVEMENTS  IN  SCIENCE 

toward  our  system,  you  would  not  perceive  the  sun  to  be  the 
brilliant  and  gorgeous  object  that  we  know  so  well.  If  you 
could  see  him  at  all,  he  would  merely  seem  like  a  star,  not 
nearly  as  bright  as  many  of  those  you  can  see  at  night.  Even 
if  you  had  the  biggest  of  telescopes  to  aid  your  vision,  you  could 
never  discern  from  one  of  these  bodies  the  planets  which  sur- 
round the  sun ;  no  astronomer  in  the  stars  could  see  Jupiter, 
even  if  his  sight  were  a  thousand  times  as  powerful  as  any 
sight  or  telescope  that  we  know.  So  minute  an  object  as  our 
earth  would,  of  course,  be  still  more  hopelessly  beyond  the  pos- 
sibility of  vision. 

THE  NUMBER  OF  THE  STARS 

To  count  the  stars  involves  a  task  which  lies  beyond  the 
power  of  man  to  accomplish.  Even  without  the  aid  of  any 
telescope,  we  can  see  a  great  multitude  of  stars  from  this  part 
of  the  world.  There  are  also  many  constellations  in  the  south- 
ern hemisphere  which  never  appear  above  our  horizon.  If, 
however,  we  were  to  go  to  the  equator,  then,  by  waiting  there 
for  a  twelvemonth,  all  the  stars  in  the  heavens  would  have  been 
successively  exposed  to  view.  An  astronomer,  Houzeau,  with 
the  patience  to  count  them,  enumerated  about  six  thousand. 
This  is  the  naked-eye  estimate  of  the  star-population  of  the 
heavens ;  but  if  instead  of  relying  on  unaided  vision,  you  get 
the  assistance  of  a  little  telescope,  you  will  be  astounded  at  the 
enormous  multitude  of  stars  which  are  disclosed. 

An  ordinary  opera-glass  or  binocular  is  a  very  useful  instru- 
ment for  looking  at  the  stars  in  the  heavens.  If  you  employ 
an  instrument  of  this  sort,  you  will  be  amazed  to  find  that  the 
heavens  teem  with  additional  hosts  of  stars  that  your  unaided 
vision  would  never  have  given  you  knowledge  of.  Any  part  of 
the  sky  may  be  observed;  but,  just  to  give  an  illustration,  take 
one  special  region,  namely,  that  of  the  Great  Bear.  Of  these 
seven  well-known  stars,  four  form  a  sort  of  oblong,  while  the 
other  three  represent  the  tail.  I  would  like  you  to  make  this 
little  experiment.  On  a  fine  clear  night,  count  how  many  stars 
there  are  within  this  oblong ;  they  are  all  very  faint,  but  you 


ASTRONOMY  151 

will  be  able  to  see  a  few,  and,  with  good  sight,  and  on  a  clear 
night,  you  may  see  perhaps  ten.  Next  take  your  opera-glass 
and  sweep  it  over  the  same  region ;  if  you  will  carefully  count 
the  stars  it  shows,  you  will  find  fully  two  hundred ;  so  that  the 
opera-glass  has,  in  this  part  of  the  sky,  revealed  nearly  twenty 
times  as  many  stars  as  could  be  seen  without  its  aid.  As  6,000 
stars  can  be  seen  by  the  eye  all  over  the  heavens,  we  may  fairly 
expect  that  twenty  times  that  number — that  is  to  say,  120,000 
stars — could  be  shown  by  the  opera-glass  over  the  entire  sky. 
Let  us  go  a  step  further,  and  employ  a  telescope,  the  object- 
glass  of  which  is  three  inches  across.  This  is  a  useful  tele- 
scope to  have,  and,  if  a  good  one,  will  show  multitudes  of  pleas- 
ing objects,  though  an  astronomer  would  not  consider  it  very 
powerful.  An  instrument  like  this,  small  enough  to  be  carried 
in  the  hand,  has  been  applied  to  the  task  of  enumerating  the 
stars  in  the  northern  half  of  the  sky,  and  320,000  stars  were 
counted.  Indeed,  the  actual  number  that  might  have  been  seen 
with  it  is  considerably  greater,  for  when  the  astronomer  Arge- 

ider  made  this  memorable  investigation  he  was  unable  to 
reckon  many  of  the  stars  in  localities  where  they  lay  very  close 
together.  This  grand  count  only  extended  to  half  the  sky,  and, 

iuming  that  the  other  half  is  as  richly  inlaid  with  stars,  we 
that  a  little  telescope  like  that  we  have  supposed  will,  when 

/ept  over  the  heavens,  reveal  more  than  one  hundred  times 
as  many  stars  as  our  eyes  could  possibly  reveal.  Still,  we  are 
only  at  the  beginning  of  the  count ;  the  very  great  telescopes 
add  largely  to  the  number.  There  are  multitudes  of  stars 
which  in  small  instruments  we  cannot  see,  but  which  are  dis- 
tinctly visible  from  our  great  observatories.  That  telescope 
would  be  still  but  a  comparatively  small  one  which  would  show 
6,000,000 ;  and  with  the  greatest  instruments,  the  tale  of  stars 
has  risen  to  over  50,000,000. 

In  addition  to  those  stars  which  the  largest  telescopes  show 
us,  there  are  myriads  which  make  their  presence  evident  in  a 
wholly  different  way.  It  is  only  in  quite  recent  times  that  an 
attempt  has  been  made  to  develop  fully  the  powers  of  photog- 
raphy in  representing  the  celestial  objects.  On  a  photographic 
)late  which  has  been  exposed  to  the  sky  in  a  great  telescope 


152  ACHIEVEMENTS  IN  SCIENCE 

the  stars  are  recorded  by  thousands.  Many  of  these  may,  of 
course,  be  observed  with  a  good  telescope,  but  there  are  not  a 
few  others  which  no  one  ever  saw  in  a  telescope,  which  appar- 
ently no  one  ever  could  see,  though  the  photograph  is  able  to 
show  them.  We  do  not,  however,  employ  a  camera  like  that 
which  the  photographer  uses  who  is  going  to  take  your  por- 
trait. The  astronomer's  plate  is  put  into  his  telescope,  and 
then  the  telescope  is  turned  towards  the  sky.  On  that  plate 
the  stars  produce  their  images,  each  by  its  own  light.  Some 
of  these  images  are  excessively  faint,  but  we  give  a  very  long 
exposure  of  an  hour  or  two  hours ;  sometimes  as  much  as  four 
hours'  exposure  is  given  to  a  plate  so  sensitive  that  a  mere 
fraction  of  a  second  would  sufficiently  expose  it  during  the 
ordinary  practice  of  taking  a  photograph  in  daylight. 

We  thus  afford  sufficient  time  to  enable  the  fainter  objects 
to  indicate  their  presence  upon  the  sensitive  film.  Even  with 
an  exposure  of  a  single  hour  a  picture  exhibiting  16,000  stars 
has  been  taken.  Yet  the  portion  of  the  sky  which  it  represents 
is  only  one  ten-thousandth  part  of  the  entire  heavens. 

Here,  at  last,  we  have  obtained  some  conception  of  the 
sublime  scale  on  which  the  stellar  universe  is  constructed. 
Yet  even  these  plates  cannot  represent  all  the  stars  that  the 
heavens  contain.  We  have  every  reason  for  knowing  that  with 
larger  telescopes,  with  more  sensitive  plates,  with  more  pro- 
longed exposures,  ever  fresh  myriads  of  stars  will  be  brought 
into  our  view. 

You  must  remember  that  every  one  of  these  stars  is  truly 
a  sun,  a  lamp,  as  it  were,  which  doubtless  gives  light  to  other 
objects  in  its  neighborhood  as  our  sun  sheds  light  upon  this 
earth  and  the  other  planets.  In  fact,  to  realize  the  glories  of 
the  heavens  you  should  try  to  think  that  the  brilliant  points 
you  see  are  merely  the  luminous  points  of  the  otherwise  invisi- 
ble universe. 

Standing  one  fine  night  on  the  deck  of  a  Cunarder  we  passed 
in  open  ocean  another  great  Atlantic  steamer.  The  vessel  was 
near  enough  for  us  to  see  not  only  the  light  from  the  mast-head 
but  also  the  little  beams  from  the  several  cabin  ports ;  and  we 
could  see  nothing  of  the  ship  herself.  Her  very  existence  was 


ASTRONOMY  153 

only  known  to  us  by  the  twinkle  of  these  lights.  Doubtless 
her  passengers  could  see,  and  did  see,  the  similar  lights  from 
our  own  vessel,  and  they  probably  drew  the  correct  inference 
that  these  lights  indicated  a  great  ship. 

Consider  the  multiplicity  of  beings  and  objects  in  a  ship :  the 
captain  and  the  crew,  the  passengers,  the  cabins,  the  engines, 
the  boats,  the  rigging,  and  the  stores.  Think  of  all  the  varied 
interests  there  collected,  and  then  reflect  that  out  on  the  ocean, 
at  night,  the  sole  indication  of  the  existence  of  this  elaborate 
structure  was  given  by  the  few  beams  of  light  that  happened 
to  radiate  from  it.  Now  raise  your  eyes  to  the  stars ;  there  are 
the  twinkling  lights.  We  cannot  see  what  those  lights  illumi- 
nate, we  can  only  conjecture  what  untold  wealth  of  non-lumi- 
nous bodies  may  also  lie  in  their  vicinity ;  we  may,  however, 
feel  certain  that  just  as  the  few  gleaming  lights  from  a  ship  are 
utterly  inadequate  to  give  a  notion  of  the  nature  and  the  con- 
tents of  an  Atlantic  steamer,  so  are  the  twinkling  stars  utterly 
inadequate  to  give  even  the  faintest  conception  of  the  extent 
and  the  interest  of  the  universe.  We  merely  see  self-luminous 
bodies,  but  of  the  multitudes  of  objects  and  the  elaborate  sys- 
tems of  which  these  bodies  are  only  the  conspicuous  points  we 
see  nothing  and  we  know  very  little.  We  are,  however,  enti- 
tled to  infer  from  an  examination  of  our  own  star — the  sun — 
and  of  the  beautiful  system  by  which  it  is  surrounded,  that 
these  other  suns  may  be  also  splendidly  attended.  This  is 
quite  as  reasonable  a  supposition  as  that  a  set  of  lights  seen  at 
night  on  the  Atlantic  Ocean  indicates  the  existence  of  a  fine 
ship. 

THE  CLUSTERS  OF  STARS 

On  a  clear  night  you  can  often  see,  stretching  across  the 
sky,  a  track  of  faint  light,  which  is  known  to  astronomers  as 
the  "  Milky  Way."  It  extends  below  the  horizon,  and  then 
round  the  earth  to  form  a  girdle  about  the  heavens.  WThen  we 
examine  the  Milky  Way  with  a  telescope  we  find,  to  our  amaze- 
ment, that  it  consists  of  myriads  of  stars,  so  small  and  so  faint 
that  we  are  not  able  to  distinguish  them  individually ;  we  merely 
see  the  glow  produced  from  their  collective  rays.  Remember- 


154  ACHIEVEMENTS  IN  SCIENCE 

ing  that  our  sun  is  a  star,  and  that  the  Milky  Way  surrounds 
us,  it  would  almost  seem  as  if  our  sun  were  but  one  of  the  host 
of  stars  which  form  this  cluster. 

There  are  also  other  clusters  of  stars,  some  of  which  are 
exquisitely  beautiful  telescopic  spectacles.  I  may  mention  a 
celebrated  pair  of  these  objects  which  lies  in  the  constellation 
of  Perseus.  The  sight  of  them  in  a  great  telescope  is  so  im- 
posing that  no  one  who  is  fit  to  look  through  a  telescope  could 
resist  a  shout  of  wonder  and  admiration  when  first  they  burst 
on  his  view.  But  there  are  other  clusters,  such  as  that  which 
is  known  as  the  "  Globular  Cluster  in  the  Centaur."  It  con- 
sists of  a  ball  of  stars,  so  far  off  that,  however  large  these 
several  suns  may  actually  be,  they  have  dwindled  down  to  ex- 
tremely small  points  of  light.  A  homely  illustration  may  serve 
to  show  the  appearance  which  a  globular  cluster  presents  in  a 
good  telescope.  Take  a  pepper-caster,  and  on  a  sheet  of  white 
paper,  shake  out  the  pepper  until  there  is  a  little  heap  at  the 
center  and  other  grains  are  scattered  loosely  about.  Imagine 
that  every  one  of  those  grains  of  pepper  was  to  be  transformed 
into  a  tiny  electric  light,  and  then  you  have  some  idea  of  what 
a  cluster  of  stars  would  look  like  when  viewed  through  a  tele- 
scope of  sufficient  power.  There  are  multitudes  of  such  groups 
scattered  through  the  depths  of  space.  They  require  our  big- 
gest telescopes  to  show  them  adequately.  We  have  seen  that 
our  sun  is  a  star,  being  only  one  of  a  magnificent  cluster  that 
forms  the  Milky  Way.  We  have  also  seen  that  there  are  other 
groups  scattered  through  the  length  and  depth  of  space.  It  is 
thus  we  obtain  a  notion  of  the  rank  which  our  earth  holds  in 
the  scheme  of  things  celestial. 

THE  DISTANCES  OF  THE  STARS 

Now  about  the  distances  of  the  stars.  I  shall  not  make  the 
attempt  to  explain  fully  how  astronomers  make  such  measure- 
ments, but  I  will  give  you  some  notion  of  how  it  is  done.  We 
make  the  two  observations  from  two  opposite  points  on  the 
earth's  orbit,  which  are  therefore  at  a  distance  of  186,000,000 
miles.  Imagine  that  on  Midsummer  Day,  when  standing  on  the 


ASTRONOMY  155 

earth  here,  I  measured  with  a  piece  of  card  the  angle  between 
the  star  and  the  sun.  Six  months  later  on,  on  Midwinter  Day, 
when  the  earth  is  at  the  opposite  point  of  its  orbit,  I  again 
measure  the  angle  between  the  same  star  and  the  sun,  and  we 
can  now  determine  the  star's  distance  by  making  a  triangle.  I 
draw  a  line  a  foot  long,  and  we  will  take  this  foot  to  represent 
186,000,000  miles,  the  distance  between  the  two  stations;  then 
placing  the  cards  at  the  corners,  I  rule  the  two  sides  and  com- 
plete the  triangle,  and  the  star  must  be  at  the  remaining  corner ; 
then  I  measure  the  sides  of  the  triangle,  and  how  many  feet 
they  contain,  and  recollecting  that  each  foot  corresponds  to 
186,000,000  miles,  we  discover  the  distance  of  the  star.  If  the 
stars  were  comparatively  near  us,  the  process  would  be  a  very 
simple  one ;  but,  unfortunately,  the  stars  are  so  extremely  far 
off  that  this  triangle,  even  with  a  base  of  only  one  foot,  must 
have  its  sides  many  miles  long.  Indeed,  astronomers  will  tell 
you  that  there  is  no  more  delicate  or  troublesome  work  in  the 
whole  of  their  science  than  that  of  discovering  the  distance  of 
a  star. 

In  all  such  measurements  we  take  the  distance  from  the 
earth  to  the  sun  as  a  conveniently  long  measuring-rod,  whereby 
to  express  the  results.  The  nearest  stars  are  still  hundreds  of 
thousands  of  times  as  far  off  as  the  sun.  Let  us  ponder  for  a 
little  on  the  vastness  of  these  distances.  We  shall  first  express 
them  in  miles.  Taking  the  sun's  distance  to  be  93,000,000 
miles,  then  the  distance  of  the  nearest  fixed  star  is  about 
twenty  millions  of  millions  of  miles — that  is  to  say,  we  express 
this  by  putting  down  a  2  first,  and  then  writing  thirteen  ciphers 
after  it.  It  is,  no  doubt,  easy  to  speak  of  such  figures,  but  it  is 
a  very  different  matter  when  we  endeavor  to  imagine  the  awful 
magnitude  which  such  a  number  indicates.  I  must  try  to  give 
some  illustrations  which  will  enable  you  to  form  a  notion  of  it. 
At  first  I  was  going  to  ask  you  to  try  and  count  this  number, 
but  when  I  found  it  would  require  at  least  300,000  years,  count- 
ing day  and  night  without  stopping,  before  the  task  was  over, 
it  became  necessary  to  adopt  some  other  method. 

When  on  a  visit  in  Lancashire  I  was  once  kindly  permitted 
to  visit  a  cotton  mill,  and  I  learned  that  the  cotton  yarn  there 


156  ACHIEVEMENTS  IN  SCIENCE 

produced  in  a  single  day  would  be  long  enough  to  wind  round 
this  earth  twenty-seven  times  at  the  equator.  It  appears  that 
the  total  production  of  cotton  yarn  each  day  in  all  the  mills  to- 
gether would  be  on  the  average  about  155,0x30,000  miles.  In 
fact,  if  they  would  only  spin  about  one-fifth  more,  we  could 
assert  that  Great  Britain  produced  enough  cotton  yarn  every 
day  to  stretch  from  the  earth  to  the  sun  and  back  again !  It  is 
not  hard  to  find  from  these  figures  how  long  it  would  take  for 
all  the  mills  in  Lancashire  to  produce  a  piece  of  yarn  long 
enough  to  reach  from  our  earth  to  the  nearest  of  the  stars.  If 
the  spinners  worked  as  hard  as  ever  they  could  for  a  year,  and 
if  all  the  pieces  were  then  tied  together,  they  would  extend  to 
only  a  small  fraction  of  the  distance ;  nor  if  they  worked  for  ten 
years,  or  for  twenty  years,  would  the  task  be  fully  accomplished. 
Indeed,  upwards  of  four  hundred  years  would  be  necessary  be- 
fore enough  cotton  could  be  grown  in  America  and  spun  in  this 
country  to  stretch  over  a  distance  so  enormous.  All  the  spin- 
ning that  has  ever  yet  been  done  in  the  world  has  not  formed 
a  long  enough  thread ! 

There  is  another  way  in  which  we  can  form  some  notion  of 
the  immensity  of  these  sidereal  distances.  You  will  recollect 
that,  when  we  were  speaking  of  Jupiter's  moons,  I  told  you  of 
the  beautiful  discovery  which  their  eclipses  enabled  astronomers 
to  make.  It  was  thus  found  that  light  travels  at  the  enormous 
speed  of  about  185,000  miles  per  second.  It  moves  so  quickly 
that  within  a  single  second  a  ray  would  flash  two  hundred  times 
from  London  to  Edinburgh  and  back  again. 

We  said  that  a  meteor  travels  one  hundred  times  as  swiftly 
as  a  rifle-bullet ;  but  even  this  great  speed  seems  almost  noth- 
ing when  compared  with  the  speed  of  light,  which  is  10,000 
times  as  great.  Suppose  some  brilliant  outbreak  of  light  were 
to  take  place  in  a  distant  star — an  outbreak  which  would  be  of 
such  intensity  that  the  flash  from  it  would  extend  far  and  wide 
throughout  the  universe.  The  light  would  start  forth  on  its 
voyage  with  terrific  speed.  Any  neighboring  star  which  was 
at  a  distance  of  less  than  185,000  miles  would,  of  course,  see 
the  flash  within  a  second  after  it  had  been  produced.  More 
distant  bodies  would  receive  the  intimation  after  intervals  of 


ASTRONOMY  157 

time  proportioned  to  their  distances.  Thus,  if  a  body  were 
1,000,000  miles  away,  the  light  would  reach  it  in  from  five  to 
six  seconds,  while  over  a  distance  as  great  as  that  which  sepa- 
rates the  earth  from  the  sun  the  news  would  be  carried  in  about 
eight  minutes.  We  can  calculate  how  long  a  time  must  elapse 
ere  the  light  shall  travel  over  a  distance  so  great  as  that  be- 
tween the  star  and  our  earth.  You  will  find  that  from  the 
nearest  of  the  stars  the  time  required  for  the  journey  will  be 
over  three  years.  Ponder  on  all  that  this  involves  That  out- 
break in  the  star  might  be  great  enough  to  be  visible  here,  but 
we  could  never  become  aware  of  it  till  three  years  after  it  had 
happened.  When  we  are  looking  at  such  a  star  to-night  we  do 
not  see  it  as  it  is  at  present,  for  the  light  that  is  at  this  moment 
entering  our  eyes  has  traveled  so  far  that  it  has  been  three 
years  on  the  way.  Therefore,  when  we  look  at  the  star  now 
we  see  it  as  it  was  three  years  previously.  In  fact,  if  the  star 
were  to  go  out  altogether,  we  might  still  continue  to  see  it 
twinkling  for  a  period  of  three  years  longer,  because  a  certain 
amount  of  light  was  on  its  way  to  us  at  the  moment  of  extinc- 
tion, and  so  long  as  that  light  keeps  arriving  here,  so  long  shall 
we  see  the  star  showing  as  brightly  as  ever.  When,  therefore, 
you  look  at  the  thousands  of  stars  in  the  sky  to-night,  there  is 
not  one  that  you  see  as  it  is  now,  but  as  it  was  years  ago. 

I  have  been  speaking  of  the  stars  that  are  nearest  to  us,  but 
there  are  others  much  farther  off.  It  is  true  we  cannot  find 
the  distances  of  these  more  remote  objects  with  any  degree  of 
accuracy,  but  we  can  convince  ourselves  how  great  that  distance 
is  by  the  following  reasoning.  Look  at  one  of  the  brightest 
stars.  Try  to  conceive  that  the  object  was  carried  away  farther 
into  the  depths  of  space,  until  it  was  ten  times  as  far  from  us 
as  it  is  at  present,  it  would  still  remain  bright  enough  to  be 
recognized  in  quite  a  small  telescope ;  even  if  it  were  taken  to 
one  hundred  times  its  original  distance  it  would  not  have  with- 
drawn from  the  view  of  a  good  telescope ;  while  if  it  retreated 
one  thousand  times  as  far  as  it  was  at  first  it  would  still  be  a 
recognizable  point  in  our  mightiest  instruments.  Among  the 
stars  which  we  can  see  with  our  telescopes,  we  feel  confident 
there  must  be  many  from  which  the  light  has  expended  hun- 


158  ACHIEVEMENTS  IN  SCIENCE 

dreds  of  years,  or  even  thousands  of  years,  on  the  journey. 
When,  therefore,  we  look  at  such  objects,  we  see  them,  not  as 
they  are  now,  but  as  they  were  ages  ago ;  in  fact,  a  star  might 
have  ceased  to  exist  for  thousands  of  years,  and  still  be  seen  by 
us  every  night  as  a  twinkling  point  in  our  great  telescopes. 

Remembering  these  facts,  you  will,  I  think,  look  at  the 
heavens  with  a  new  interest.  There  is  a  bright  star,  Vega,  or 
Alpha  Lyrae,  a  beautiful  gem,  so  far  off  that  the  light  from  it 
which  now  reaches  our  eyes  started  before  many  of  my  audi- 
ence were  born.  Suppose  that  there  are  astronomers  residing 
on  worlds  amid  the  stars,  and  that  they  have  sufficiently  power- 
ful telescopes  to  view  this  globe,  what  do  you  think  they  would 
observe  ?  They  will  not  see  our  earth  as  it  is  at  present ;  they 
will  see  it  as  it  was  years  (and  sometimes  many  years)  ago. 
There  are  stars  from  which  if  England  could  now  be  seen,  the 
whole  of  the  country  would  be  observed  at  this  present  moment 
to  be  in  a  great  state  of  excitement  at  a  very  auspicious  event. 
Distant  astronomers  might  notice  a  great  procession  in  Lon- 
don, and  they  could  watch  the  coronation  of  the  youthful  queen, 
Queen  Victoria,  amid  the  enthusiasm  of  a  nation.  There  are 
other  stars  still  further,  from  which,  if  the  inhabitants  had  good 
enough  telescopes,  they  would  now  see  a  mighty  battle  in  prog- 
ress not  far  from  Brussels.  One  splendid  army  could  be  be- 
held hurling  itself  time  after  time  against  the  immovable  ranks 
of  the  other.  There  can  be  no  doubt  that  there  are  stars  so 
far  away  that  the  rays  of  light  which  started  from  the  earth  on 
the  day  of  the  battle  of  Waterloo  are  only  just  arriving  there. 
Farther  off  still,  there  are  stars  from  which  a  bird's-eye  view 
could  be  taken  at  this  very  moment  of  the  signing  of  Magna 
Charta.  There  are  even  stars  from  which  England,  if  it  could 
be  seen  at  all,  would  now  appear,  not  as  the  great  England  we 
know,  but  as  a  country  covered  by  dense  forests,  and  inhabited 
by  painted  savages,  who  waged  incessant  war  with  wild  beasts 
that  roamed  through  the  island.  The  geological  problems  that 
now  puzzle  us  would  be  quickly  solved  could  we  only  go  far 
enough  into  space  and  had  we  only  powerful  enough  tele- 
scopes. We  should  then  be  able  to  view  our  earth  through  the 
successive  epochs  of  past  geological  time ;  we  should  be  actu- 


ASTRONOMY  159 

ally  able  to  see  those  great  animals  whose  fossil  remains  are 
treasured  in  our  museums,  tramping  about  over  the  earth's  sur- 
face, splashing  across  its  swamps,  or  swimming  with  broad  flip- 
pers through  its  oceans.  Indeed,  if  we  could  view  our  own 
earth  reflected  from  mirrors  in  the  stars,  we  might  still  see 
Moses  crossing  the  Red  Sea,  or  Adam  and  Eve  being  expelled 
from  Eden. 

DOUBLE  STARS 

Whenever  you  have  a  chance  of  looking  at  the  heavens 
through  a  telescope,  you  should  ask  to  be  shown  what  is  called 
a  double  star.  There  are  many  stars  in  the  heavens  which  pre- 
sent no  remarkable  appearance  to  the  unaided  eye,  but  which  a 
good  telescope  at  once  shows  to  be  of  quite  a  complex  nature. 
These  are  what  we  call  double  stars,  in  which  two  quite  dis- 
tinct stars  are  placed  so  close  together  that  the  unaided  eye  is 
unable  to  separate  them.  Under  the  magnifying  power  of  the 
telescope,  however,  they  are  seen  to  be  distinct.  In  order  to 
give  some  notion  of  what  these  objects  are  like,  I  shall  briefly 
describe  three  of  them.  The  first  lies  in  that  best  known  con- 
stellation, the  Great  Bear.  If  you  look  at  his  tail,  which  con- 
sists of  three  stars,  you  will  see  that  near  the  middle  one  of  the 
three  a  small  star  is  situated ;  we  call  this  little  star  Alcor,  but 
it  is  the  brighter  one  near  Alcor  to  which  I  specially  call  your 
attention.  The  sharpest  eye  would  never  suspect  that  it  was 
composed  of  two  stars  placed  close  together.  Even  a  small 
telescope  will,  however,  show  this  to  be  the  case,  and  this  is 
the  easiest  and  the  first  observation  that  a  young  astronomer 
should  make  when  beginning  to  turn  a  telescope  to  the  heavens. 
Of  course  you  will  not  imagine  that  I  mean  Alcor  to  be  the 
second  component  of  the  double  star ;  it  is  the  bright  star  near 
Alcor  which  is  the  double.  Here  are  two  marbles,  and  these 
marbles  are  fastened  an  inch  apart.  You  can  see  them,  of 
course,  to  be  separate ;  but  if  the  pair  were  moved  further  and 
further  away,  then  you  would  soon  not  be  able  to  distinguish 
between  them,  though  the  actual  distance  between  the  marbles 
had  not  altered.  Look  at  these  two  wax  tapers  which  are  now 
lighted;  the  little  flames  are  an  inch  apart.  You  would  have 


160  ACHIEVEMENTS  IN  SCIENCE 

to  view  them  from  a  station  a  third  of  a  mile  away  if  the  dis- 
tance between  the  two  flames  were  to  appear  the  same  as  that 
between  the  two  components  of  this  double  star.  Your  eye 
would  never  be  able  to  discriminate  between  two  lights  only  an 
inch  apart  at  so  great  a  distance ;  a  telescope  would,  however, 
enable  you  to  do  so,  and  this  is  the  reason  why  we  have  to  use 
telescopes  to  show  us  double  stars. 

You  might  look  at  that  double  star  year  after  year  through- 
out the  course  of  a  long  life  without  finding  any  appreciable 
change  in  the  relative  positions  of  its  components.  But  we 
know  that  there  is  no  such  thing  as  rest  in  the  universe ;  even 
if  you  could  balance  a  body  so  as  to  leave  it  for  a  moment  at 
rest,  it  would  not  stay  there,  for  the  simple  reason  that  all  the 
bodies  round  it  in  every  direction  are  pulling  at  it,  and  it  is  cer- 
tain that  the  pull  in  one  direction  will  preponderate,  so  that 
move  it  must.  Especially  is  this  true  in  the  case  of  two  suns 
like  those  forming  a  double  star.  Placed  comparatively  near 
each  other  they  could  not  remain  permanently  in  that  position ; 
they  must  gradually  draw  together  and  come  into  collision  with 
an  awful  crash.  There  is  only  one  way  by  which  such  a  disas- 
ter could  be  averted.  That  is  by  making  one  of  these  stars 
revolve  around  the  other  just  as  the  earth  revolves  around  the 
sun,  or  the  moon  revolves  around  the  earth.  Some  motion 
must,  therefore,  be  going  on  in  every  genuine  double  star, 
whether  we  have  been  able  to  see  that  motion  or  not. 

Let  us  now  look  at  another  double  star  of  a  different  kind. 
This  time  it  is  in  the  constellation  of  Gemini.  The  heavenly 
twins  are  called  Castor  and  Pollux.  Of  these,  Castor  is  a  very 
beautiful  double  star,  consisting  of  two  bright  points,  a  great 
deal  closer  together  than  were  those  in  the  Great  Bear;  con- 
sequently a  better  telescope  is  required  for  the  purpose  of 
showing  them  separately.  Castor  has  been  watched  for  many 
years,  and  it  can  be  seen  that  one  of  these  stars  is  slowly  re- 
volving around  the  other;  but  it  takes  a  very  long  time, 
amounting  to  hundreds  of  years,  for  a  complete  circuit  to  be 
accomplished.  This  seems  very  astonishing,  but  when  you  re- 
member how  exceedingly  far  Castor  is,  you  will  perceive  that 
that  pair  of  stars  which  appear  so  close  together  that  it  requires 


ASTRONOMY  161 

a  telescope  to  show  them  apart  must  indeed  be  separated  by 
hundreds  of  millions  of  miles.  Let  us  try  to  conceive  our  own 
system  transformed  into  a  double  star.  If  we  took  our  outer- 
most planet — Neptune — and  enlarged  him  a  good  deal,  and 
then  heated  him  sufficiently  to  make  him  glow  like  a  sun,  he 
would  still  continue  to  revolve  round  our  sun  at  the  same  dis- 
tance, and  thus  a  double  star  would  be  produced.  An  inhabi- 
tant of  Castor  who  turned  his  telescope  towards  us  would  be 
able  to  see  the  sun  as  a  star.  He  would  not,  of  course,  be  able 
to  see  the  earth,  but  he  might  see  Neptune  like  another  small 
star  close  to  the  sun.  If  generations  of  astronomers  in  Castor 
continued  their. observations  of  our  system,  they  would  find  a 
binary  star,  of  which  one  component  took  a  century  and  a  half 
to  go  round  the  other.  Need  we  then  be  surprised  that  when 
we  look  at  Castor  we  observe  movements  that  seem  very  slow  ? 

There  is  often  so  much  diffused  light  about  the  bright  stars 
seen  in  a  telescope,  and  so  much  twinkling  in  some  states  of 
the  atmosphere,  that  stars  appear  to  dance  about  in  rather  a 
puzzling  fashion,  especially  to  one  who  is  not  accustomed  to 
astronomical  observations.  I  remember  hearing  how  a  gentle- 
man once  came  to  visit  an  observatory.  The  astronomer 
showed  him  Castor  through  a  powerful  telescope  as  a  fine  speci- 
men of  a  double  star,  and  then,  by  way  of  improving  his  little 
lesson,  the  astronomer  mentioned  that  one  of  these  stars  was 
revolving  around  the  other.  "  Oh,  yes,"  said  the  visitor,  "  I 
saw  them  going  round  and  round  in  the  telescope."  He  would, 
however,  have  had  to  wait  for  a  few  centuries  with  his  eye  to 
the  instrument  before  he  would  have  been  entitled  to  make  this 
assertion. 

Double  stars  also  frequently  delight  us  by  giving  beauti- 
fully contrasted  colors.  I  dare  say  you  have  often  noticed  the 
red  and  the  green  lights  that  are  used  on  railways  in  the  signal 
lamps.  Imagine  one  of  those  red  and  one  of  those  green  lights 
away  far  up  in  the  sky  and  placed  close  together,  then  you 
would  have  some  idea  of  the  appearance  that  a  colored  double 
star  presents,  though  perhaps  I  should  add  that  the  hues  in  the 

ivenly  bodies  are  not  so  vividly  different  as  are  those  which 
ir  railway  people  find  necessary.  There  is  a  particularly 


162  ACHIEVEMENTS  IN  SCIENCE 

beautiful  double  star  of  this  kind  in  the  constellation  of  the 
Swan.  You  could  make  an  imitation  of  it  by  boring  two  holes, 
with  a  red-hot  needle,  in  a  piece  of  card,  and  then  covering  one 
of  these  holes  with  a  small  bit  of  the  topaz-colored  gelatine 
with  which  Christmas  crackers  are  made.  The  other  star  is  to 
be  similarly  colored  with  blue  gelatine.  A  slide  made  on  this 
principle  placed  in  the  lantern  gives  a  very  good  representation 
of  these  two  stars  on  the  screen.  There  are  many  other  colored 
doubles  besides  this  one ;  and,  indeed,  it  is  noteworthy  that  we 
hardly  ever  find  a  blue  or  a  green  star  by  itself  in  the  sky ;  it 
is  always  as  a  member  of  one  of  these  pairs. 

WHAT  THE  STARS  ARE  MADE  OF 

Here  is  a  piece  of  stone.  If  I  wanted  to  know  what  it  was 
composed  of,  I  should  ask  a  chemist  to  tell  me.  He  would 
take  it  into  his  laboratory,  and  first  crush  it  into  powder,  and 
then,  with  his  test  tubes,  and  with  the  liquids  which  his  bottles 
contain,  and  his  weighing  scales,  and  other  apparatus,  he  would 
tell  all  about  it ;  there  is  so  much  of  this,  and  so  much  of  that, 
and  plenty  of  this,  and  none  at  all  of  that.  But  now,  suppose 
you  ask  this  chemist  to  tell  you  what  the  sun  is  made  of,  or  one 
of  the  stars.  Of  course,  you  have  not  a  sample  of  it  to  give 
him ;  how,  then,  can  he  possibly  find  out  anything  about  it  ? 
Well,  he  can  tell  you  something,  and  this  is  the  wonderful  dis- 
covery that  I  want  to  explain  to  you.  We  now  put  down  the 
gas  and  I  kindle  a  brilliant  red  light.  Perhaps  some  of  those 
whom  I  see  before  me  have  occasionally  ventured  on  the  some- 
what dangerous  practice  of  making  fireworks.  If  there  is  any 
boy  here  who  has  ever  constructed  sky-rockets,  and  put  the 
little  balls  into  the  top  which  are  to  burn  with  such  vivid  colors 
when  the  explosion  takes  place,  he  will  know  that  the  sub- 
stance which  tinged  that  fire  red  must  have  been  strontium. 
He  will  recognize  it  by  the  color ;  because  strontium  gives  a 
red  light  which  nothing  else  will  give.  Here  are  some  of  these 
lightning  papers,  as  they  are  called ;  they  are  very  pretty  and 
very  harmless;  and  these,  too,  give  brilliant  red  flashes  as  I 
throw  them.  The  red  tint,  has,  no  doubt,  been  produced  by 


ASTRONOMY  163 

strontium  ak*o.     You  see  we  recognized  the  substance  simply 
by  the  color  of  the  light  it  produced  when  burning. 

There  are,  in  nature,  a  number  of  simple  bodies  called  ele- 
ments. Every  one  of  these,  when  ignited  under  suitable  con- 
ditions, emits  a  light  which  belongs  to  it  alone,  and  by  which 
it  can  be  distinguished  from  every  other  substance.  Many  of 
the  materials  will  yield  light  which  will  require  to  be  studied 
by  much  more  elaborate  artifices  than  those  which  have  sufficed 
for  us.  But  you  will  see  that  the  method  affords  a  means  of 
finding  out  the  actual  substances  present  in  the  sun  or  in  the 
stars.  There  is  a  practical  difficulty  in  the  fact  that  each  of 
the  heavenly  bodies  contains  a  number  of  different  elements ; 
so  that  in  the  light  it  sends  us  the  hues  arising  from  distinct 
substances  are  blended  into  one  beam.  The  first  thing  to  be 
done  is  to  get  some  way  of  splitting  up  a  beam  of  light,  so  as 
to  discover  the  components  of  which  it  is  made.  You  might 
have  a  skein  of  silks  of  different  hues  tangled  together,  and  this 
would  be  like  the  sunbeam  as  we  receive  it  in  its  un sorted  con- 
dition. How  shall  we  untangle  the  light  from  the  sun  or  a 
star  ?  I  will  show  you  by  a  simple  experiment.  Here  is  a  beam 
from  the  electric  light ;  beautifully  white  and  bright,  is  it  not  ? 
It  looks  so  pure  and  simple,  but  yet  that  beam  is  composed  of 
all  sorts  of  colors  mingled  together,  in  such  proportions  as  to 
form  white  light.  I  take  a  wedge-shaped  piece  of  glass  called 
a  prism,  and  when  I  introduce  it  into  the  course  of  the  beam, 
you  see  the  transformation  that  has  taken  place.  Instead  of 
the  white  light  you  have  now  all  the  colors  of  the  rainbow — 
red,  orange,  yellow,  green,  blue,  indigo,  violet.  These  colors 
are  very  beautiful,  but  they  are  transient,  for  the  moment  we 
take  away  the  prism  they  all  unite  again  to  form  white  light. 
You  see  what  the  prism  has  done ;  it  has  bent  all  the  light  in 
passing  through  it ;  but  it  is  more  effective  in  bending  the  blue 
than  the  red,  and  consequently  the  blue  is  carried  away  much 
farther  than  the  red.  Such  is  the  way  in  which  we  study  the 
composition  of  a  heavenly  body.  We  take  a  beam  of  its  light, 
we  pass  it  through  a  prism,  and  immediately  it  is  separated 
into  its  components ;  then  we  compare  what  we  find  with  the 
lights  given  by  the  different  elements,  and  thus  we  are  enabled 


164  ACHIEVEMENTS  IN  SCIENCE 

to  discover  the  substances  which  exist  in  the  distant  object 
whose  light  we  have  examined.  I  do  not  mean  to  say  that  the 
method  is  a  simple  one ;  all  I  am  endeavoring  to  show  is  a  gen- 
eral outline  of  the  way  in  which  we  have  discovered  the  mate- 
rials present  in  the  stars.  The  instrument  that  is  employed 
for  this  purpose  is  called  the  spectroscope.  And  perhaps  you 
may  remember  that  name  by  these  lines,  which  I  have  heard 
from  an  astronomical  friend : — 

"  Twinkle,  twinkle,  little  star, 
Now  we  find  out  what  you  are, 
When  unto  the  midnight  sky 
We  the  spectroscope  apply." 

I  am  sure  it  will  interest  everybody  to  know  that  the  ele- 
ments which  the  stars  contain  are  not  altogether  different  from 
those  of  which  the  earth  is  made.  It  is  true  there  may  be  sub- 
stances in  the  stars  of  which  we  know  nothing  here ;  but  it  is 
certain  that  many  of  the  most  common  elements  on  the  earth 
are  present  in  the  most  distant  bodies.  I  shall  only  mention 
one,  the  metal  iron.  That  useful  substance  has  been  found  in 
some  of  the  stars  which  lie  at  almost  incalculable  distances 
from  the  earth. 

THE  NEBULA 

I  must  say  a  few  words  about  some  dim  and  mysterious 
objects  to  which  we  have  not  yet  alluded.  They  are  what  are 
called  nebulae,  or  little  clouds;  and  in  one  sense  they  are  justly 
called  little,  for  each  of  them  occupies  but  a  very  small  spot  in 
the  sky  as  compared  with  that  which  would  be  filled  by  an  or- 
dinary cloud  in  our  air.  The  nebulae  are,  however,  objects  of 
the  most  stupendous  proportions.  Were  our  earth  and  thou- 
sands of  millions  of  bodies  quite  as  big  all  put  together,  they 
would  not  be  nearly  so  great  as  one  of  these  nebulae.  Astrono- 
mers reckon  up  the  various  nebulae  by  thousands,  but  I  must 
add  that  most  of  them  are  apparently  faint  and  uninteresting. 
A  nebula  is  sometimes  liable  to  be  mistaken  for  a  comet.  The 
comet  is,  as  I  have  already  explained,  at  once  distinguished  by 
the  fact  that  it  is  moving  and  changing  its  appearance  from 


ASTRONOMY  165 

hour  to  hour,  while  scores  of  years  elapse  without  changes  in 
the  aspect  or  position  of  a  nebula.  The  most  powerful  tele- 
scopes are  employed  in  observing  these  faint  objects.  A  curi- 
ous object  in  the  constellation  of  Lyra  can  be  seen  under  differ- 
ent telescopic  powers.  This  is  a  gigantic  ring  of  luminous 
gas.  To  judge  of  the  size  of  this  ring  let  us  suppose  that  a 
railway  were  laid  across  it,  and  the  train  you  entered  at  one 
side  was  not  to  stop  until  it  reached  the  other  side,  how  long 
do  you  think  this  journey  would  require?  Let  the  train  start 
at  a  speed  of  a  mile  a  minute ;  you  would  think,  surely,  that  it 
must  soon  cross  the  ring.  But  the  minutes  pass,  an  hour  has 
elapsed;  so  the  distance  must  be  sixty  miles  at  all  events. 
The  hours  creep  on  into  days,  the  days  advance  into  years,  and 
still  the  train  goes  on.  The  years  would  lengthen  out  into 
centuries,  and  even  when  the  train  had  been  rushing  on  for  a 
thousand  years  with  an  unabated  speed  of  a  mile  a  minute  the 
journey  would  certainly  not  have  been  completed.  Nor  do  I 
venture  to  say  what  ages  must  elapse  ere  the  terminus  at  the 
other  side  of  the  ring  nebula  would  be  reached. 

A  cluster  of  stars  viewed  in  a  small  telescope  will  often  seem 
like  a  nebula,  for  the  rays  of  the  stars  become  blended.  A 
powerful  telescope  will,  however,  dispel  the  illusion  and  reveal 
the  separate  stars.  It  was,  therefore,  thought  that  all  the 
nebulae  might  be  merely  clusters  so  exceedingly  remote  that 
our  mightiest  instruments  failed  to  resolve  them  into  stars. 
But  this  is  now  known  not  to  be  the  case.  Many  of  these  ob- 
jects are  really  masses  of  glowing  gas ;  such  are,  for  instance, 
the  ring  nebulae,  of  which  I  have  just  spoken. 


ASTRONOMY 

Comets 

By  CAMILLE  FLAMMARION 

r\  AHESE  tailed  bodies,  which  suddenly  come  to  light  up  the 
JL  heavens,  were  for  long  regarded  with  terror,  like  so  many 
warning  signs  of  Divine  wrath.  Men  have  always  thought 
themselves  much  more  important  than  they  really  are  in  the 
universal  order ;  they  have  had  the  vanity  to  pretend  that  the 
whole  creation  was  made  for  them,  whilst  in  reality  the  whole 
creation  does  not  suspect  their  existence.  The  earth  we  in- 
habit is  only  one  of  the  smallest  worlds,  and  therefore  it  can 
scarcely  be  for  it  alone  that  all  the  wonders  of  the  heavens,  of 
which  the  immense  majority  remains  hidden  from  it,  were 
created.  In  this  disposition  of  man  to  see  in  himself  the  center 
and  the  end  of  everything,  it  was  easy  indeed  to  consider  the 
steps  of  Nature  as  unfolded  in  his  favor ;  and  if  some  unusual 
phenomenon  presented  itself,  it  was  considered  to  be  without 
doubt  a  warning  from  Heaven.  If  these  illusions  had  had  no 
other  result  than  the  amelioration  of  the  more  timorous  of  the 
community  one  would  regret  these  ages  of  ignorance ;  but  not 
only  were  these  fancied  warnings  of  no  use,  seeing  that,  once 
the  danger  passed,  man  returned  to  his  former  state ;  but  they 
also  kept  up  among  people  imaginary  terrors,  and  revived  the 
fatal  resolutions  caused  by  the  fear  of  the  end  of  the  world. 

When  one  fancies  the  world  is  about  to  end — and  this  has 
been  believed  for  more  than  a  thousand  years — no  solicitude 
is  felt  in  the  work  of  improving  this  world ;  and,  by  the  indiffer- 
ence or  disdain  into  which  one  falls,  periods  of  famine  and  gen- 
eral misery  are  induced  which  at  certain  times  have  overtaken 

166 


ASTRONOMY  167 

our  community.  Why  use  the  wealth  of  a  world  which  is  going 
to  perish  ?  Why  work,  be  instructed,  or  rise  in  the  progress  of 
the  sciences  or  art?  Much  better  to  forget  the  world,  and 
absorb  one's  self  in  the  barren  contemplation  of  an  unknown 
life.  It  is  thus  that  ages  of  ignorance  weigh  on  man,  and 
thrust  him  further  and  further  into  darkness,  while  science 
makes  known,  by  its  influence  on  the  whole  community,  its 
great  value  and  the  magnitude  of  its  aim. 

The  history  of  a  comet  would  be  an  instructive  episode  of 
the  great  history  of  the  heavens.  In  it  could  be  brought  to- 
gether the  description  of  the  progressive  movement  of  human 
thought,  as  well  as  the  astronomical  theory  of  these  extraordi- 
nary bodies.  Let  us  take,  for  example,  one  of  the  most  memo- 
rable and  best-known  comets,  and  give  an  outline  of  its  succes- 
sive passages  near  the  earth.  Like  the  planetary  worlds, 
comets  belong  to  the  solar  system,  and  are  subject  to  the  rule 
of  the  Star  King.  It  is  the  universal  law  of  gravitation  which 
guides  their  path ;  solar  attraction  governs  them,  as  it  governs 
the  movement  of  the  planets  and  the  small  satellites.  The 
chief  point  of  difference  between  them  and  the  planets  is,  that 
their  orbits  are  very  elongated;  and,  instead  of  being  nearly 
circular,  they  take  the  elliptical  form.  In  consequence  of  the 
nature  of  these  orbits,  the  same  comet  may  approach  very  near 
the  sun,  and  afterward  travel  from  it  to  immense  distances. 
Thus,  the  period  of  the  comet  of  1680  has  been  estimated  at 
3,000  years.  It  approaches  the  sun,  so  as  to  be  nearer  to  it 
than  our  moon  is  to  us,  whilst  it  recedes  to  a  distance  eight 
hundred  and  fifty-three  times  greater  than  the  distance  of  the 
earth  from  the  sun.  On  the  seventeenth  of  December,  1680, 
it  was  at  its  perihelion — that  is,  at  its  greatest  proximity  to  the 
sun ;  it  is  now  continuing  its  path  beyond  the  Neptunian  orbit. 
Its  velocity  varies  according  to  its  distance  from  the  solar  body. 
At  its  perihelion  it  travels  thousands  of  leagues  per  minute ;  at 
its  aphelion  it  does  not  pass  over  more  than  a  few  yards.  Its 
proximity  to  the  sun  in  its  passage  near  that  body  caused 
Newton  to  think  that  it  received  a  heat  28,000  times  greater 
than  that  we  experience  at  the  summer  solstice ;  and  that  this 
heat  being  2,000  times  greater  than  that  of  red-hot  iron,  an 


168  ACHIEVEMENTS  IN  SCIENCE 

iron  globe  of  the  same  dimensions  would  be  50,000  years  en- 
tirely losing  its  heat.  Newton  added  that  in  the  end  comets 
will  approach  so  near  the  sun  that  they  will  not  be  able  to 
escape  the  preponderance  of  its  attraction,  and  that  they  will 
fall  one  after  the  other  into  this  brilliant  body,  thus  keeping  up 
the  heat  which  it  perpetually  pours  out  into  space.  Such  is 
the  deplorable  end  assigned  to  comets  by  the  author  of  the 
"Principia,"  an  end  which  makes  De  la  Bre"tonne  say  to  R£tif : 
"  An  immense  comet,  already  larger  than  Jupiter,  was  again  in- 
creased in  its  path  by  being  blended  with  six  other  dying 
comets.  Thus  displaced  from  its  ordinary  route  by  these  slight 
shocks,  it  did  not  pursue  its  true  elliptical  orbit ;  so  that  the 
unfortunate  thing  was  precipitated  into  the  devouring  center  of 
the  sun."  "It  is  said,"  added  he,  "that  the  poor  comet,  thus 
burned  alive,  sent  forth  dreadful  cries ! " 

It  will  be  interesting,  then,  in  a  double  point  of  view,  to  fol- 
low a  comet  in  its  different  passages  in  sight  of  the  earth. 
Let  us  take  the  most  important  in  astronomical  history — the 
one  whose  orbit  has  been  calculated  by  Edmund  Halley,  and 
which  was  named  after  him.  It  was  in  1682  that  this  comet 
appeared  in  its  greatest  brilliancy,  accompanied  with  a  tail 
which  did  not  measure  less  than  thirty-two  millions  of  miles. 
By  the  observation  of  the  path  which  it  described  in  the 
heavens,  and  the  time  it  occupied  in  describing  it,  this  astrono- 
mer calculated  its  orbit,  and  recognized  that  the  comet  was  the 
same  as  that  which  was  admired  in  1531  and  1607,  and  which 
ought  to  have  reappeared  in  1759.  Never  did  scientific  predic- 
tion excite  a  more  lively  interest.  The  comet  returned  at  the 
appointed  time;  and  on  the  twelfth  of  March,  1759,  reached  its 
perihelion.  Since  the  year  12  before  the  Christian  era,  it  had 
presented  itself  twenty-four  times  to  the  earth.  It  was  princi- 
pally from  the  astronomical  annals  of  China  that  it  was  possible 
to  follow  it  up  to  this  period. 

Its  first  memorable  appearance  in  the  history  of  France  is 
that  of  837,  in  the  reign  of  Louis  le  Debonnaire.  An  anony- 
mous writer  of  chronicles  of  that  time,  named  "  The  Astrono- 
mer," gave  the  following  details  of  this  appearance,  relative  to 
the  influence  of  the  comet  on  the  imperial  imagination ; 


ASTRONOMY  169 

"  During  the  holy  days  of  the  solemnization  of  Easter,  a 
phenomenon  ever  fatal,  and  of  gloomy  foreboding,  appeared  in 
the  heavens.  As  soon  as  the  Emperor,  who  paid  attention  to 
these  phenomena,  received  the  first  announcement  of  it,  he 
gave  himself  no  rest  until  he  had  called  a  certain  learned  man 
and  myself  before  him.  As  soon  as  I  arrived,  he  anxiously 
asked  me  what  I  thought  of  such  a  sign ;  I  asked  time  of  him, 
in  order  to  consider  the  aspects  of  the  stars,  and  to  discover  the 
truth  by  their  means,  promising  to  acquaint  him  on  the  mor- 
row ;  but  the  Emperor,  persuaded  that  I  wished  to  gain  time, 
which  was  true,  in  order  not  to  be  obliged  to  announce  any- 
thing fatal  to  him,  said  to  me :  '  Go  on  the  terrace  of  the  palace 
and  return  at  once  to  tell  me  what  you  have  seen,  for  I  did  not 
see  this  star  last  evening,  and  you  did  not  point  it  out  to  me ; 
but  I  know  that  it  is  a  comet ;  tell  me  what  you  think  it  an- 
nounces to  me.'  Then,  scarcely  allowing  me  time  to  say  a 
word,  he  added :  *  There  is  still  another  thing  you  keep  back ; 
it  is  that  a  change  of  reign  and  the  death  of  a  prince  are  an- 
nounced by  this  sign.'  And  as  I  advanced  the  testimony  of 
the  prophet,  who  said :  '  Fear  not  the  signs  of  the  heavens  as 
the  nations  fear  them,'  the  prince  with  his  grand  nature,  and 
the  wisdom  which  never  forsook  him,  said,  *  We  must  not  only 
fear  Him  who  has  created  both  us  and  this  star.  But  as  this 
phenomenon  may  refer  to  us,  let  us  acknowledge  it  as  a  warn- 
ing from  Heaven.' " 

Louis  le  Debonnaire  gave  himself  and  his  court  to  fasting 
and  prayer,  and  built  churches  and  monasteries.  He  died  three 
years  later,  in  840,  and  historians  have  profited  by  this  slight 
coincidence  to  prove  that  the  appearance  of  the  comet  was  a 
harbinger  of  death.  The  historian,  Raoul  Glader,  added  later : 
"  These  phenomena  of  the  universe  are  never  presented  to  man 
without  surely  announcing  some  wonderful  and  terrible  event." 

Halley's  comet  again  appeared  in  April,  1066,  at  the  mo- 
ment when  William  the  Conqueror  invaded  England.  It  was 
pretended  that  it  had  the  greatest  influence  on  the  fate  of  the 
battle  of  Hastings,  which  delivered  over  the  country  to  the 
Normans. 

A  contemporary   poet,  alluding  probably  to  the  English 


170  ACHIEVEMENTS  IN  SCIENCE 

diadem  with  which  William  was  crowned,  had  proclaimed  in 
one  place,  "  that  the  comet  had  been  more  favorable  to  William 
than  nature  had  been  to  Caesar;  the  latter  had  no  hair,  but 
William  had  received  some  from  the  comet."  A  monk  of 
Malmesbury  apostrophized  the  comet  in  these  terms :  "  Here 
thou  art  again,  thou  cause  of  the  tears  of  many  mothers !  It  is 
long  since  I  have  seen  thee,  but  I  see  thee  now,  more  terrible 
than  ever ;  thou  threatenest  my  country  with  complete  ruin !  " 

In  1455,  the  same  comet  made  a  more  memorable  appear- 
ance still.  The  Turks  and  Christians  were  at  war,  the  West 
and  the  East  seemed  armed  from  head  to  foot — on  the  point  of 
annihilating  each  other.  The  crusade  undertaken  by  Pope 
Calixtus  III.  against  the  invading  Saracens  was  waged  with 
redoubled  ardor  on  the  sudden  appearance  of  the  star  with  the 
flaming  tail.  Mahomet  II.  took  Constantinople  by  storm,  and 
raised  the  siege  of  Belgrade.  But  the  Pope  having  put  aside 
both  the  curse  of  the  comet  and  the  abominable  designs  of  the 
Mussulmans,  the  Christians  gained  the  battle,  and  vanquished 
their  enemies  in  a  bloody  fight.  The  Angelus  to  the  sound  of 
bells  dates  from  these  ordinances  of  Calixtus  III.  referring  to 
the  comet. 

This  ancient  comet  witnessed  many  revolutions  in  human 
history,  at  each  of  its  appearances,  even  in  its  later  ones,  in 
1682,  1759,  1835;  it  was  also  presented  to  the  earth  under  the 
most  diverse  aspects,  passing  through  a  great  variety  of  forms, 
from  the  appearance  of  a  curved  saber,  as  in  1456,  to  that  of  a 
misty  head,  as  in  its  last  visit.  Moreover,  this  is  not  an  excep- 
tion to  the  general  rule,  for  these  mysterious  stars  have  had 
the  gift  of  exercising  a  power  on  the  imagination  which  plunged 
it  in  ecstasy  or  trouble.  Swords  of  fire,  bloody  crosses,  flam- 
ing daggers,  spears,  dragons,  fish,  and  other  appearances  of  the 
same  kind,  were  given  to  them  in  the  Middle  Ages  and  the 
Renaissance. 

Comets  like  those  of  1577  appear,  moreover,  to  justify  by 
their  strange  form  the  titles  with  which  they  are  generally 
greeted.  The  most  serious  writers  were  not  free  from  this 
terror.  Thus,  in  a  chapter  on  celestial  monsters,  the  celebrated 
surgeon,  Ambroise  Pare",  described  the  comet  of  1528  under 


ASTRONOMY  171 

the  most  vivid  and  frightful  colors :  "  This  comet  was  so  hor- 
rible and  dreadful  that  it  engendered  such  great  terror  to  the 
people,  that  they  died,  some  with  fear,  others  with  illness.  It 
appeared  to  be  of  immense  length,  and  of  blood  color;  at  its 
head  was  seen  the  figure  of  a  curved  arm,  holding  a  large  sword 
in  the  hand  as  if  it  wished  to  strike.  At  the  point  of  the  sword 
there  were  three  stars,  and  on  either  side  was  seen  a  great 
number  of  hatchets,  knives,  and  swords  covered  with  blood, 
amongst  which  were  numerous  hideous  human  faces,  with 
bristling  beards  and  hair." 

The  imagination  has  good  eyes  when  it  exerts  itself.  The 
great  and  strange  variety  of  cometary  aspects  is  described  with 
exactitude  by  Father  Souciet  in  his  Latin  poem  on  comets. 
"Most  of  them,"  says  he,  "shine  with  fires  interlaced  like 
thick  hair,  and  from  this  they  have  taken  the  name  of  comets. 
One  draws  after  it  the  twisted  folds  of  a  long  tail ;  another  ap- 
pears to  have  a  white  and  bushy  beard ;  this  one  throws  a  glim- 
mer similar  to  that  of  a  lamp  burning  during  the  night ;  that 
one,  O  Titan !  represents  thy  resplendent  face ;  and  this  other, 
O  Phcebe!  the  form  of  thy  nascent  horns.  There  are  some 
which  bristle  with  twisted  serpents.  Shall  I  speak  of  those 
armies  which  have  sometimes  appeared  in  the  air?  of  those 
clouds  which  follow  as  it  were  along  a  circle,  or  which  resemble 
the  head  of  Medusa  ?  Have  there  not  often  been  seen  figures 
of  men  or  savage  animals  ? 

"  Often,  in  the  gloom  of  night,  lighted  up  by  these  sad  fires, 
the  horrible  sound  of  arms  is  heard,  the  clashing  of  swords  which 
meet  in  the  clouds,  the  ether  furiously  resounding  with  fearful 
din  which  crush  the  people  with  terror.  All  comets  have  a 
melancholy  light,  but  they  have  not  all  the  same  color.  Some 
have  a  leaden  color ;  others  that  of  flame  or  brass.  The  fires 
of  some  have  the  redness  of  blood ;  others  resemble  the  bright- 
ness of  silver.  Some  again  are  azure;  others  have  the  dark 
and  pale  color  of  iron.  These  differences  come  from  the  di- 
versity of  the  vapors  which  surround  them,  or  from  the  differ- 
ent manner  in  which  they  receive  the  sun's  rays.  Do  you  not 
see  in  our  fires,  that  various  kinds  of  wood  produce  different 
colors  ?  Pines  and  firs  give  a  flame  mixed  with  thick  smoke, 


172  ACHIEVEMENTS  IN  SCIENCE 

and  throw  out  little  light.  That  which  rises  from  sulphur  and 
thick  bitumen  is  bluish.  Lighted  straw  gives  out  sparks  of  a 
reddish  color.  The  large  olive,  laurel,  ash  of  Parnassus,  etc., 
trees  which  always  retain  their  sap,  throw  a  whitish  light  simi- 
lar to  that  of  a  lamp.  Thus,  comets  whose  fires  are  formed  of 
different  materials  each  take  and  preserve  a  color  which  is 
peculiar  to  them." 

Instead  of  being  a  cause  of  fear  and  terror,  the  variety  and 
variability  of  the  aspect  of  comets  ought  rather  to  indicate  to 
us  the  harmlessness  of  their  nature. 


GEOLOGY 
The  Glacial  Epoch  and  Primitive  Man 

By  ALFRED  RUSSEL  WALLACE 

THE  foundations  of  modern  geology  were  laid,  in  the  latter 
part  of  the  last  century,  by  Werner,  Hutton,  and  William 
Smith,  but  most  of  the  details  and  some  of  the  more  important 
principles  have  been  wholly  worked  out  during  the  present 
century.  The  great  landmarks  of  its  progress  can  alone  be  re- 
ferred to  here,  namely  ( i )  the  establishment  by  Lyell  of  what 
has  been  termed  the  uniformitarian  theory  5(2)  the  proof  of 
a  recent  glacial  epoch  and  the  working  out  of  its  effects  upon 
the  earth's  surface;  and  (3)  the  discovery  that  man  in  the 
northern  hemisphere  lived  contemporaneously  with  many  now 
extinct  animals. 

In  the  early  part  of  the  century,  and  so  late  as  the  year 
1830,  Cuvier's  "Essay  on  the  Theory  of  the  Earth"  held  the 
field  as  the  exponent  of  geological  theory.  A  fifth  edition  of 
the  English  translation  appeared  in  1827,  and  a  German  trans- 
lation so  late  as  1 830.  In  this  work  it  was  maintained  that 
almost  all  geological  phenomena  pointed  to  a  state  of  the  earth 
and  of  natural  forces  very  different  from  what  now  exists.  In 
the  raised  beds  of  shells,  in  fractured  rocks,  in  vertical  stratifi- 
cation, we  were  said  to  have  proofs  "  that  the  surface  of  the 
globe  has  been  broken  up  by  revolutions  and  catastrophes." 
The  differences  in  the  character  of  adjacent  stratified  deposits 
showed  that  there  must  have  been  various  successive  irruptions 
of  the  sea  over  the  land ;  and  Cuvier  maintained  that  these 
irruptions  and  retreats  of  the  sea  were  not  slow  or  gradual, 
"  but  that  most  of  the  catastrophes  which  have  occasioned  them 

173 


174  ACHIEVEMENTS  IN  SCIENCE 

have  been  sudden."  He  urged  that  the  sharp  and  bristling 
ridges  and  peaks  of  the  primitive  mountains  "  are  indications  of 
the  violent  manner  in  which  they  have  been  elevated " ;  and 
he  concludes  that  "  it  is  in  vain  we  search  among  the  powers 
which  now  act  at  the  surface  of  the  earth  for  causes  sufficient 
to  produce  the  revolutions  and  catastrophes,  the  traces  of 
which  are  exhibited  in  its  crust."  This  theory  of  convulsions 
and  catastrophes  held  almost  universal  sway  within  the  memory 
of  persons  now  living;  for  although  Hutton  and  Playfair  had 
advanced  far  more  accurate  views,  they  appear  to  have  made 
little  impression,  while  the  great  authority  attached  to  Cuvier's 
name  carried  all  before  it. 

But  in  1830,  while  Cuvier  was  at  the  height  of  his  fame,  and 
his  book  was  still  being  translated  into  foreign  languages,  a 
hitherto  unknown  writer  published  the  first  volume  of  a  work 
which  struck  at  the  very  roots  of  the  catastrophe  theory,  and 
demonstrated,  by  a  vast  array  of  facts  and  the  most  cogent 
reasoning,  that  almost  every  portion  of  it  was  more  or  less 
imaginary  and  in  opposition  to  the  plainest  teachings  of  nature. 
The  victory  was  complete.  From  the  date  of  the  publication 
of  the  "  Principles  of  Geology  "  there  were  no  more  English 
editions  of  "The  Theory  of  the  Earth." 

Ly ell's  method  was  that  of  a  constant  appeal  to  the  processes 
of  nature.  Before  asserting  that  certain  results  could  not  be 
due  to  existing  causes  he  carefully  observed  what  those  causes 
were  now  doing.  He  applied  to  them  the  tests  of  accurate 
measurement,  and  he  showed  that,  taking  into  account  the  ele- 
ment of  long-continued  action,  they  were,  in  almost  every  case, 
fully  adequate  to  explain  the  observed  phenomena.  He  showed 
that  modern  volcanoes  had  poured  out  equally  vast  masses  of 
melted  rock,  which  had  covered  equally  large  areas,  with  any 
ancient  volcano ;  that  strata  were  now  forming,  comparable  in 
extent  and  thickness  with  any  ancient  strata ;  that  organic  re- 
mains were  being  preserved  in  them,  just  as  in  the  older  forma- 
tions ;  that  land  was  almost  everywhere  either  rising  or  sinking, 
as  of  old ;  that  valleys  were  being  excavated  and  mountains 
worn  away ;  that  earthquake  shocks  were  producing  faults  in 
the  rocks ;  that  vegetation  was  now  preparing  future  coal-beds ; 


ALFRED   RUSSEL  WALLACE. 


GEOLOGY  175 

that  limestones,  sandstones,  metamorphic  and  igneous  rocks 
were  still  being  formed ;  and  that,  given  time,  and  the  intermit- 
tent or  continuous  action  of  the  causes  we  can  now  trace  in 
operation,  all  the  contortions  and  fractures  of  strata,  all  the 
ravines  and  precipices,  and  every  other  modification  of  the 
earth's  crust  supposed  to  imply  the  agency  of  sudden  revolu- 
tions and  violent  catastrophes  may  be  again  and  again  produced. 

During  a  period  of  more  than  forty  years  Sir  Charles  Lyell 
continued  to  enlarge  and  improve  his  work,  bringing  out  eleven 
editions,  the  last  of  which  was  published  three  years  before  his 
death ;  and  rarely  has  any  scientific  work  so  completely  justified 
its  title,  since  it  remains  to  this  day  the  best  exposition  of  the 
"  Principles  of  Geology  " — the  foundation  on  which  the  science 
itself  must  be  and  has  been  built.  The  disciples  and  followers 
of  Lyell  have  been  termed  "  Uniformitarians,"  on  account  of 
their  belief  that  the  causes  which  produced  the  phenomena 
manifested  to  us  in  the  crust  of  the  earth  are  essentially  of  the 
same  nature  as  those  acting  now.  And,  as  is  often  the  case, 
the  use  of  the  term  as  a  nickname  has  led  to  a  misconception 
as  to  the  views  of  those  to  whom  it  is  applied.  A  few  words 
on  this  point  are  therefore  called  for. 

Modern  objectors  say  that  it  is  unphilosophical  to  maintain 
that  in  our  little  expe.  ience  of  a  few  hundred,  or  at  most  a  few 
thousand,  years,  we  can  have  witnessed  all  forms  and  degrees 
of  the  action  of  natural  forces ;  that  we  have  no  right  to  take 
the  historical  period  as  a  fair  sample  of  all  past  geological  ages ; 
and  that,  as  a  mere  matter  of  probability,  we  ought  to  expect 
to  find  proofs  of  greater  earthquakes,  more  violent  eruptions, 
more  sudden  upheavals,  and  more  destructive  floods,  having 
occurred  during  the  vast  eons  of  past  time.  Now  this  argu- 
ment is  perfectly  sound  if  limited  to  the  occurrence  of  extreme 
cases,  but  not  if  applied  to  averages.  No  Uniformitarian  will 
deny  the  probability  of  there  having  been  some  greater  convul- 
sions in  past  geological  ages  than  have  ever  been  experienced 
during  the  historical  period.  But  modern  convulsionists  do  not 
confine  themselves  to  this  alone,  but  maintain  that,  as  a  rule, 
all  the  great  natural  forces  tending  to  modify  the  surface  of  the 
earth  were  more  powerful  and  acted  on  a  larger  scale  than  they 


176  ACHIEVEMENTS  IN  SCIENCE 

do  now.  On  the  ground  of  mere  probability,  however,  we  have 
no  right  to  assume  a  diminution  rather  than  an  increase  of 
natural  forces  in  recent  times,  unless  there  is  some  proof  that 
these  forces  have  diminished.  Sir  Charles  Lyell  shows  that 
the  cases  adduced  as  indicating  greater  forces  in  the  past  are 
fallacious,  and  his  doctrine  is  simply  one  of  real  as  against 
imaginary  forces. 

But  our  modern  objectors  have  another  argument,  founded 
upon  the  admitted  fact  that  the  earth  has  cooled  and  is  slowly 
cooling,  and  was  probably  once  in  a  molten  condition.  They 
urge  that  in  early  geological  times,  when  the  earth  was  hotter, 
the  igneous,  aqueous,  and  aerial  forces  were  necessarily  greater, 
and  would  produce  more  rapid  changes  and  greater  convulsions 
than  now.  This  is  a  purely  theoretical  conclusion,  by  no  means 
sure,  and  perhaps  the  very  reverse  of  what  really  occurred. 
There  are  two  reasons  for  this  belief,  which  may  be  very  briefly 
stated.  After  the  earth's  crust  was  once  formed  it  cooled  very 
slowly,  and  the  crust  became  very  gradually  thicker.  So  far  as 
the  action  of  the  molten  interior  on  the  crust  may  have  pro- 
duced convulsions  they  should  become  not  less,  but  more  vio- 
lent as  the  crust  becomes  thicker.  With  a  thin  crust  any  in- 
ternal tension  will  be  more  frequently  relieved  by  fracture  or 
bending,  and  the  resulting  disturbances  will  be  less  violent; 
but  as  the  crust  becomes  thicker,  internal  tensions  will  accumu- 
late, and  when  relieved  by  fracture  the  disturbance  will  be  more 
violent. 

As  regards  storms  and  other  aerial  disturbances,  these  also 
would  probably  be  less  violent  when  the  temperature  of  the 
whole  surface  was  more  uniform  as  well  as  warmer,  and  the  at- 
mosphere consequently  so  full  of  vapor  as  to  prevent  the  sun's 
rays  from  producing  the  great  inequalities  of  temperature  that 
now  prevail.  It  is  these  inequalities  that  produce  the  great 
aerial  disturbances  of  our  era,  which  arise  from  the  heated  sur- 
faces of  the  bare  plains  and  deserts  of  the  subtropical  and  warm 
temperate  belts.  In  the  equatorial  belt  (10°  each  side  of  the 
equator),  where  the  heat  is  more  uniform  and  the  surface  gen- 
erally well  clothed  with  vegetation,  tornadoes  and  hurricanes 
are  almost  unknown. 


GEOLOGY  177 

There  remains  only  the  action  of  the  tides  upon  coasts  and 
estuaries,  which  may  have  been  greater  in  early  geological 
times,  if,  as  is  supposed,  the  moon  was  then  considerably  nearer 
to  the  earth  than  it  is  now.  But  this  is  a  comparatively  unim- 
portant matter  as  regards  geological  convulsions,  because  its 
maximum  effects  recur  at  short  intervals  and  with  great  regu- 
larity, so  that  both  vegetation  and  the  higher  forms  of  animal 
life  would  necessarily  be  limited  to  the  areas  which  were  be- 
yond its  influence. 

It  thus  appears  that,  so  far  from  there  being  any  theoretical 
necessity  for  greater  violence  of  natural  forces  in  early  geologi- 
cal times,  there  are  some  weighty  reasons  why  the  opposite 
should  have  been  the  case ;  while  all  the  evidence  furnished  by 
the  rocks  themselves,  and  by  the  contours  of  the  earth's  sur- 
face, are  in  favor  of  a  general  uniformity,  with,  of  course,  con- 
siderable local  variability. 

It  is  interesting  to  note  the  very  different  explanations  of 
the  commonest  features  of  the  earth's  surface  given  by  the  old 
and  by  the  new  theories.  In  every  mountain  region  of  the 
globe  deep  valleys,  narrow  ravines,  and  lofty  precipices  are  of 
common  occurrence,  and  these  were,  by  the  old  school,  almost 
always  explained  as  being  due  to  convulsions  of  nature.  In 
ravines,  we  were  taught  that  the  rocks  had  been  "  torn  asun- 
der," while  the  mountains  and  the  precipices  were  indications 
of  "  sudden  fractures  and  upheavals  of  the  earth's  crust."  On 
the  new  theory,  these  phenomena  are  found  to  be  almost  wholly 
due  to  the  slow  action  of  the  most  familiar  every-day  causes, 
such  as  rain,  snow,  frost,  and  wind,  with  rivers,  streams,  and 
every  form  of  running  water,  acting  upon  rocks  of  varying 
hardness,  permeability,  and  solubility.  Every  shower  of  rain 
falling  upon  steep  hillsides  or  gentle  slopes,  while  partially  ab- 
sorbed, to  a  large  extent  runs  over  the  surface,  carrying  solid 
matter  from  higher  to  lower  levels.  Every  muddy  stream  or 
flooded  river  shows  the  effect  of  this  action.  Day  and  night, 
month  after  month,  year  after  year,  this  denudation  goes  on, 
and  its  cumulative  effects  are  enormous.  The  material  is  sup- 
plied from  the  solid  rocks,  fractured  and  decomposed  by  the 
agency  of  snow  and  frost  or  by  mere  variations  of  temperature, 
12 


178  ACHIEVEMENTS  IN  SCIENCE 

and  primarily  by  those  interior  earth  movements  which  are 
continually  cleaving,  fissuring,  and  faulting  the  solid  strata,  and 
thus  giving  the  superficial  causes  of  denudation  facilities  for 
action.  The  amount  and  rate  of  this  superficial  erosion  and 
denudation  of  the  earth's  surface  can  be  determined  by  the 
quantity  of  solid  matter  carried  down  by  the  rivers  to  the  sea. 
This  has  been  measured  with  considerable  accuracy  for  several 
important  rivers ;  and  by  comparing  the  quantity  of  matter, 
both  in  suspension  and  solution,  with  the  area  of  the  river 
basin,  we  know  exactly  the  average  amount  of  lowering  of 
the  whole  surface  per  annum.  It  has  thus  been  calculated 
that 

The  Mississippi  removes  one  foot  of  the  surface  of  its  basin  in 

6,000  years 

"    Ganges  "  "  "  "          2,358     " 

"    HoangHo       "  "  "  "          1,464 

"   Rhdne  "  "  "  "          1,528 

"   Danube  "  "  "  "         6,846 

"   Po  "  "  "  "  729 

"    Nith  "  "  ".  "          4,723 


The  average  of  these  rivers  gives  us  one  foot  as  the  lower- 
ing of  the  land  by  sub-aerial  denudation  in  3,000  years,  or  a 
thousand  feet  in  three  million  years ;  but  as  Europe  has  a  mean 
altitude  of  less  than  a  thousand  feet,  it  follows  that,  at  the  pres- 
ent rate  of  denudation,  the  whole  of  Europe  would  be  reduced 
to  nearly  the  sea-level  in  about  three  million  years.  Before 
this  method  of  measuring  the  rate  of  the  lowering  of  continents 
was  hit  upon  by  Mr.  Alfred  Tylor  in  1853,  no  one  imagined 
that  it  was  anything  like  so  rapid ;  and,  as  a  million  years  is 
certainly  a  short  period  as  compared  with  the  whole  geological 
record,  it  is  clear  that  elevation  must,  on  the  whole,  have  always 
kept  pace  with  the  two  lowering  agencies — sinking  and  denu- 
dation. Again,  as  in  every  continent  the  areas  occupied  by 
plains  and  lowlands,  where  denudation  is  comparatively  slow, 
are  large  as  compared  with  the  mountain  areas,  where  all  the 
denuding  agencies  are  most  powerful,  it  is  probable  that  most 
mountain  ranges  are  being  lowered  at  perhaps  ten  times  the 


GEOLOGY  179 

above  average  rate,  and  many  mountain  peaks  and  ridges  per- 
haps a  hundred  times. 

Examples  of  the  rapidity  of  denudation  as  compared  with 
earth-movements  are  to  be  found  everywhere.  In  disturbed 
regions,  faults  of  many  hundreds,  and  sometimes  even  thou- 
sands of  feet,  are  not  uncommon ;  yet  there  is  often  no  ine- 
quality on  the  surface,  indicating  that  the  dislocation  of  strata 
has  been  caused  by  small  and  often-repeated  movements,  at 
such  intervals  that  denudation  has  been  able  to  remove  the 
elevated  portion  as  it  arose.  Again,  when  the  strata  are  bent 
into  great  folds  or  undulations,  it  is  only  rarely  that  the  tops  of 
the  folds  correspond  to  ridges  and  the  depressions  to  valleys. 
Frequently  the  reverse  is  the  case,  a  valley  running  along  the 
anticlinal  line  or  structural  ridge,  while  the  synclinal  or  struc- 
tural hollow  forms  a  mountain  top ;  while,  in  other  cases,  val- 
leys cut  across  these  structural  features,  with  little  or  no  regard 
to  them.  This  results  from  the  fact  that  it  is  not  mountains 
or  mountain  ranges,  as  we  see  them,  which  have  been  raised  by 
internal  forces,  but  a  considerable  area,  already  perhaps  much 
disturbed  and  dislocated  by  earth-movements,  has  been  slowly 
raised  till  it  became  a  kind  of  table-land.  From  its  first  eleva- 
tion above  the  sea,  however,  it  would  have  been  exposed  to  rain- 
fall, and  the  water,  flowing  off  in  the  direction  of  least  resist- 
ance, would  have  formed  a  number  of  channels  radiating  from 
the  highest  portion,  and  thus  establishing  the  first  outlines  of 
a  system  of  valleys,  which  go  on  deepening  as  the  land  goes  on 
rising,  often  quite  irrespective  of  the  nature  of  the  rocks  be- 
neath. This  explains  the  close  resemblance  in  the  general 
arrangement  of  valleys  in  all  high  regions,  as  well  as  the  very 
common  phenomenon  of  a  river  crossing  the  main  range  of  a 
mountain  system  by  a  deep  gorge ;  for  this  merely  shows  that 
what  is  now  the  highest  part  of  the  range  was  at  first  lower 
than  that  where  the  river  has  its  source,  but  has  become  higher 
by  the  more  rapid  degradation  of  the  lateral  ranges,  owing  to 
their  being  formed  of  rock  which  is  more  easily  disintegrated. 
The  various  peculiarities  of  open  valley  and  narrow  gorge,  of 
sloping  mountain-side  or  lofty  precipice,  of  rivers  cutting  across 
hills,  as  in  the  South  Downs  and  at  Clifton,  when  open  plains 


180  ACHIEVEMENTS  IN  SCIENCE 

by  which  they  might  apparently  have  reached  the  sea  are  near 
at  hand,  may  be  all  explained  as  the  results  of  those  simple 
causes  which  are  everywhere  in  action  around  us.  It  was  Sir 
Charles  Lyell  who  first  convinced  the  whole  scientific  world  of 
the  efficacy  of  these  familiar  agents ;  and  the  secure  establish- 
ment of  this  doctrine  constitutes  one  of  the  great  philosophical 
landmarks  of  the  nineteenth  century. 

THE  GLACIAL  EPOCH 

The  proof  of  the  recent  occurrence  in  the  north  temperate 
zone  of  a  glacial  epoch,  during  which  large  portions  of  Europe 
and  North  America  were  buried  in  ice,  may,  from  one  point  of 
view,  be  thought  to  prove  that  other  agents  than  those  now  in 
operation  have  acted  in  past  ages,  and  thus  to  disprove  the  main 
assumption  of  the  Uniformitarians.  But,  on  the  other  hand,  its 
existence  has  been  demonstrated  by  those  very  methods  which 
Sir  Charles  Lyell  advocated — the  accurate  observation  of  what 
nature  is  doing  now ;  while  an  ice  age  really  exists  at  the  pres- 
ent time  in  Greenland,  in  the  same  latitude  as  nearly  the  whole 
of  Sweden  and  Norway,  which  enjoy  a  comparatively  mild 
climate. 

The  first  clear  statement  of  the  evidence  for  a  former  ice 
age  was  given,  in  1822,  by  a  Swiss  engineer  named  Venetz. 
He  pointed  out  that,  where  the  existing  glaciers  have  retreated, 
the  rocks  which  they  had  covered  are  often  rounded,  smoothed, 
and  polished,  or  grooved  and  striated  in  the  direction  of  the 
glacier's  motion ;  and  that,  far  away  from  any  existing  glaciers, 
there  were  to  be  seen  rocks  similarly  rounded,  polished,  and 
striated;  while  there  also  existed  old  moraine  heaps  exactly 
similar  to  those  formed  at  present ;  and  that  these  phenomena 
extended  as  far  as  the  Jura  range,  on  the  flanks  of  which  there 
were  numbers  of  huge  blocks  of  stone,  of  a  kind  not  found  in 
those  mountains,  but  exactly  similar  to  the  ancient  rocks  of  the 
main  Alpine  chain.  Hence,  he  concluded  that  glaciers  formerly 
extended  down  the  Rhdne  valley  as  far  as  the  Jura,  and  there 
deposited  those  erratic  blocks,  the  presence  of  which  had  puz- 
zled all  former  observers. 


GEOLOGY  181 

Soon  afterward,  Charpentier  and  Agassiz  devoted  them- 
selves to  the  study  of  the  records  left  by  the  ancient  glaciers ; 
and  from  that  time  to  the  present  a  band  of  energetic  workers 
in  every  part  of  the  world  have,  by  minute  observation  and 
reasoning,  established  the  fact  of  the  extension  of  glaciers,  or 
ice-sheets,  over  a  large  portion  of  the  north  temperate  zone ; 
and  have  also  determined  the  direction  of  their  motion  and  the 
thickness  of  the  ice  in  various  parts  of  their  course.  These 
conclusions  are  now  admitted  by  every  geologist  who  has  de- 
voted himself  to  the  subject,  and  are  embodied  in  the  various 
official  geological  surveys  of  the  chief  civilized  countries ;  and 
as  they  constitute  one  of  the  most  remarkable  chapters  in  the 
past  history  of  the  globe,  and  especially  as  this  great  change  of 
climate  occurred  during  the  period  of  man's  existence  on  the 
earth,  a  brief  sketch  of  the  facts  must  be  here  given. 

There  are  four  main  groups  of  phenomena  which  demon- 
strate the  former  existence  of  glaciers  in  areas  where  they  are 
now  absent:  (i)  Moraines,  and  glacial  drifts  or  gravels;  (2) 
Smoothed,  rounded,  or  planed  rocks;  (3)  Striae,  grooves,  and 
furrows  on  rock-surfaces ;  (4)  Erratics  and  perched  blocks. 

( i )  Moraines  are  formed  by  all  existing  glaciers,  consisting 
of  the  earth  and  rocks  which  fall  upon  the  ice-rivers  from  the 
sides  of  the  valleys  through  which  they  flow.  The  slow  motion 
of  the  glacier  carries  these  down  with  it,  and  they  are  deposited 
in  great  heaps  where  it  melts.  In  some  glaciers  where  the 
tributary  valleys  are  numerous  and  the  debris  that  falls  upon 
the  ice  is  abundant,  the  whole  of  the  lower  part  of  the  glacier 
for  many  miles  is  so  buried  in  it  that  the  surface  of  the  ice  can- 
not be  seen,  and  in  these  cases  there  will  be  a  continuous 
moraine  formed  across  the  valley  where  the  glacier  terminates. 
The  characteristics  of  moraines  are,  that  they  consist  of  varied 
materials,  earth,  gravel,  and  rocks  of  various  sizes  intermingled 
confusedly ;  and  they  often  form  mounds  or  ridges  completely 
across  a  valley,  except  where  "the  stream  passes  through  it, 
while  in  other  cases  they  extend  laterally  along  the  slopes  of 
the  hillsides,  where,  owing  to  the  form  of  the  valley,  the  glacier 
has  shrunk  laterally  and  left  its  lateral  moraine  behind  it.  In 
many  cases  huge  blocks  of  rock  rest  on  the  very  summit  of  a 


182  ACHIEVEMENTS  IN  SCIENCE 

moraine,  or,  in  the  case  of  lateral  moraines,  on  the  very  edge  of 
a  precipice  in  positions  where  no  known  agency  but  ice  could 
have  deposited  them.  These  are  called  "perched  blocks." 
Drifts  or  glacial  gravels  are  deposits  of  material  similar  to  that 
forming  the  moraines,  but  spread  widely  over  districts  which 
have  formerly  been  buried  in  ice.  These  are  often  partially 
formed  of  stiff  clay,  in  which  are  embedded  quantities  of 
smoothed  and  striated  stones ;  but  the  great  characteristic  of 
all  these  ice-products  is  that  the  materials  are  not  stratified — 
that  is,  sorted  according  to  their  fineness  or  coarseness,  as  is 
always  the  case  when  deposited  by  water — but  are  mingled  con- 
fusedly together,  the  large  stones  being  scattered  all  through 
the  mass,  and  usually  being  quite  as  abundant  at  the  top  as  at 
the  bottom  of  the  deposit.  Such  deposits  are  to  be  found  all 
over  the  north  and  northwest  of  our  islands,  and  are  often  well 
exhibited  in  railway  cuttings ;  and  wherever  they  are  well  de- 
veloped, and  the  materials  of  which  they  consist  differ  from 
those  forming  the  underlying  rocks,  they  are  an  almost  infalli- 
ble indication  of  the  former  existence  of  a  glacier  or  ice-sheet. 

(2)  The  smoothed  and  rounded  rocks  called  in  Switzerland 
roches  moutonn&s,  from  their  resemblance  at  a  distance  to  re- 
cumbent sheep,  are  present  in  almost  all  recently  glaciated 
mountainous  countries,  especially  where  the  rocks  are  very  hard. 
They  are  to  be  seen  in  all  the  higher  valleys  of  Wales,  the  Lake 
District,  and  Scotland,  and  on  examination  are  found  to  consist 
often  of  the  hardest  and  toughest  rocks.     In  other  cases  the 
rock  forming  the  bed  of  the  valley  is  found  to  be  planed  off 
smooth,  even  when  it  consists  of  hard  crystalline  strata  thrown 
up  at  a  high  angle,  and  which  naturally  weathers  into  a  jagged 
or  ridged  surface. 

(3)  The  smoothed  rocks  are  often  found  to  be  covered 
with  numerous  striae,  deep  grooves,  or  huge  flutings,  and  these 
are  almost  always  in  one  direction,  which  is  that  of  the  course 
of  the  glacier.     They  may  often  be  traced  in  the  same  direction 
for  miles,  and  do  not  change  in  harmony  with  the  lesser  ine- 
qualities of  the  valley,  as  they  would  certainly  do  had  they  been 
formed  by  water  action.     These  striae  and  smoothed  rocks  are 
often  found  hundreds  or  even  thousands  of  feet  above  the  floor 


GEOLOGY  183 

of  the  valley,  and  in  many  cases  a  definite  line  can  be  traced, 
above  which  the  rocks  are  rugged  and  jagged,  while  below  it 
they  are  more  or  less  rounded,  smooth,  or  polished. 

(4)  Erratic  blocks  are  among  the  most  widespread  and  re- 
markable indications  of  glacial  action,  and  they  were  the  first 
that  attracted  the  attention  of  men  of  science.  The  great 
plains  of  Denmark,  Prussia,  North  Germany,  and  Russia  are 
strewn  with  large  masses  of  granite  and  hard  metamorphic 
rocks,  and  these  rest  either  on  glacial  drift  or  on  quite  different 
rocks  of  Secondary  or  Tertiary  age.  In  parts  of  North  Ger- 
many they  are  so  abundant  as  to  hide  the  natural  surface,  and 
they  are  often  piled  up  in  irregular  heaps  forming  hills  of 
granite  bowlders  covered  with  forests  of  pine,  birch,  and  juni- 
per. Many  of  these  blocks  are  more  than  a  thousand  tons' 
weight,  and  almost  all  of  them  can  be  traced  to  the  mountains 
of  Scandinavia  as  their  source.  Many  of  the  largest  blocks 
have  been  carried  furthest  from  the  parent  rock — a  fact  which 
is  conclusive  against  their  having  been  brought  to  their  present 
position  by  the  action  of  floods. 

The  most  interesting  and  instructive  erratic  blocks  are 
those  found  upon  the  slopes  of  the  Jura,  because  they  have 
been  most  carefully  studied  by  Swiss  and  French  geologists,  and 
have  all  been  traced  to  their  sources  in  the  Alpine  chain.  The 
Jura  mountains  consist  wholly  of  Secondary  limestones,  and 
are  situated  opposite  to  the  Bernese  Alps,  at  a  distance  of 
about  fifty  miles.  Along  their  slopes  for  a  distance  of  a  hun- 
dred miles,  and  extending  from  their  base  to  a  height  of  2,000 
feet  above  the  Lake  of  Neuchatel,  are  great  numbers  of  rocks, 
some  of  them  as  large  as  houses,  and  always  quite  different 
from  that  of  which  the  Jura  range  is  formed.  These  have  all 
been  traced  to  their  parent  rocks  in  various  parts  of  the  course 
of  the  old  glacier  of  the  Rhone,  and,  what  is  even  more  re- 
markable, their  distribution  is  such  as  to  prove  that  they  were 
conveyed  by  a  glacier  and  not  by  floating  ice  during  a  period 
of  submergence.  The  rocks  and  other  debris  that  fall  upon  a 
glacier  from  the  two  sides  of  its  main  valley  form  distinct 
moraines  upon  its  surface,  and  however  far  the  glacier  may 
flow,  and  however  much  it  may  spread  out  where  the  valley 


184  ACHIEVEMENTS  IN  SCIENCE 

widens,  they  preserve  their  relative  position  so  that  whenever 
they  are  deposited  by  the  melting  of  the  glacier,  those  that 
came  from  the  north  side  of  the  valley  will  remain  completely 
separated  from  those  which  came  from  the  south  side.  It  was 
this  fact  which  convinced  Sir  Charles  Lyell  that  the  theory  of 
floating  ice,  which  he  had  first  adopted,  would  not  explain  the 
distribution  of  the  erratics,  and  he  has  given  in  his  "  Antiquity 
of  Man "  (4th  ed.,  p.  344)  a  map  showing  the  course  of  the 
blocks  as  they  were  conveyed  on  the  surface  of  the  glacier  to 
their  several  destinations.  Other  blocks  are  found  on  the 
lower  slopes  of  the  Alpine  chain  toward  Bern  on  one  side  and 
Geneva  on  the  other,  while  the  French  geologists  have  traced 
them  down  the  Rhone  valley  seventy  miles  from  Geneva,  and 
also  more  than  twenty  miles  west  of  the  Jura,  thus  proving 
that  at  the  lowest  portion  of  that  chain  the  glacier  flowed  com- 
pletely over  it.  In  all  these  cases  the  blocks  can  be  traced  to 
a  source  corresponding  to  their  position  on  the  theory  of  glacier 
action.  Some  of  these  rocks  have  been  carried  considerably 
more  than  two  hundred  miles,  proving  that  the  old  glacier  of 
the  Rhdne  extended  to  this  enormous  distance  from  its  source. 

In  our  own  islands  and  in  North  America  these  various 
classes  of  evidence  have  been  carefully  studied,  the  direction  of 
the  glacial  striae  everywhere  ascertained,  and  all  the  more  re- 
markable erratic  blocks  traced  to  their  sources,  with  the  result 
that  the  extent  and  thickness  of  the  various  glaciers  and  ice- 
sheets  are  well  determined  and  the  direction  of  motion  of  the 
ice  ascertained.  The  conclusions  arrived  at  are  very  extraordi- 
nary, and  must  be  briefly  indicated. 

In  Great  Britain,  during  the  earlier  and  later  phases  of  the 
ice  age,  all  the  mountains  of  Scotland,  the  Lake  District,  and 
Wales  produced  their  own  glaciers,  which  flowed  down  to  the 
sea.  But  at  the  time  of  the  culmination  of  the  Glacial  Epoch 
the  Scandinavian  ice-sheet  extended  on  the  southeast  till  it 
filled  up  the  Baltic  Sea  and  spread  over  the  plains  of  north- 
western Europe,  and  also  filled  up  the  North  Sea,  joining  the 
glaciers  of  Scotland,  forming  with  them  a  continuous  ice-sheet 
from  which  the  highest  mountains  alone  protruded.  At  the 
same  time  this  Scotch  ice-sheet  extended  into  the  Irish  Sea, 


GEOLOGY  185 

and  united  with  the  glaciers  of  the  Lake  District,  Wales,  and 
Ireland  till  almost  continuous  ice-sheets  enveloped  those  coun- 
tries also.  Glacial  striae  are  found  up  to  a  height  of  3,50x3  feet 
in  Scotland  and  2,500  feet  in  the  Lake  District  and  in  Ireland; 
while  the  Isle  of  Man  was  completely  overflowed,  as  shown  by 
glacial  striae  on  the  summit  of  its  loftiest  mountains.  Erratics 
from  Scandinavia  are  found  in  great  quantities  on  Flamborough 
Head,  mixed  with  others  from  the  Lake  District  and  Galloway, 
showing  that  two  ice  streams  met  here  from  opposite  directions. 
Erratics  from  Scotland  are  also  found  in  the  Lake  District,  in 
North  Wales,  in  the  Isle  of  Man,  and  in  Ireland,  from  which 
the  direction  of  the  moving  ice  can  be  determined.  Great 
numbers  of  local  rocks  have  also  been  carried  into  places  far 
from  their  origin,  and  in  every  case  this  displacement  is  in  the 
direction  of  the  flow  of  the  ice  as  ascertained  by  the  other  evi- 
dence— never  in  the  opposite  direction.  Each  great  mountain 
area  had,  however,  its  own  center  of  local  dispersal,  depending 
upon  the  position  of  greatest  thickness  of  the  ice-sheet,  which 
was  not  necessarily  that  of  the  highest  mountains,  but  was  ap- 
proximately the  center  of  the  main  area  of  glaciation.  Thus 
the  center  of  the  North  Wales  ice-sheet  was  not  at  Snowdon, 
but  over  the  Arenig  mountains,  which  thus  became  a  local 
center  of  dispersal  of  erratics.  In  Ireland,  the  mountains  being 
placed  around  the  coasts,  the  great  central  plain  became  filled 
with  ice  which,  continually  accumulating,  formed  a  huge  dome 
of  ice  whose  outward  pressure  caused  motion  in  all  directions 
till  checked  by  the  opposing  motion  of  the  great  Scandinavian 
ice-sheet.  This  strange  fact  has  been  demonstrated  by  the 
work  of  the  Irish  Geological  Survey  and  by  many  local  geolo- 
gists, and  is  universally  accepted  by  all  who  have  studied  the 
evidence.  The  great  outlines  of  the  phenomena  of  the  ice  age 
in  our  islands  are  now  as  thoroughly  well  established  as  any  of 
the  admitted  conclusions  of  geological  science.  In  our  own 
country  the  ice  extended  more  or  less  completely  over  the 
whole  of  the  midland  counties  and  as  far  south  as  the  Thames 
Valley. 

When  we  cross  the  Atlantic  the  phenomena  are  equally  re- 
markable.    The  whole  of  the  northeastern  United  States  and 


186  ACHIEVEMENTS  IN  SCIENCE 

Canada  were  also  buried  in  an  ice-sheet  of  enormous  thickness 
and  extent.  It  came  southward  as  far  as  New  York,  and  in- 
land, in  an  irregular  line,  by  Cincinnati,  to  St.  Louis  on  the 
Mississippi.  The  whole  of  the  region  to  the  north  of  this  line 
is  covered  with  a  deposit  of  drift,  often  of  enormous  thickness, 
while  embedded  in  the  drift,  or  scattered  over  its  surface,  are 
numbers  of  blocks  and  rock-masses,  often  formed  of  materials 
quite  foreign  to  the  bed-rock  of  the  district.  These  erratics 
have  in  many  cases  been  traced  to  their  sources,  sometimes  six 
hundred  miles  away,  and  the  study  of  these,  and  of  the  numer- 
ous grooved  and  striated  rocks,  show  that  the  center  of  dispersal 
was  far  north  of  the  Alleghanies  and  its  outliers,  and,  as  in  the 
case  of  Ireland,  must  have  consisted  of  a  huge  dome  of  ice  situ- 
ated over  the  plateau  to  the  north  of  the  Great  Lakes,  in  what 
must  have  been  an  area  of  great  snow-fall  combined  with  a 
very  low  temperature.  The  maximum  thickness  of  this  great 
ice-sheet  must  have  been  at  least  a  mile  over  a  considerable 
portion  of  its  area,  as  glacial  deposits  have  been  found  on  the 
summit  of  Mount  Washington  at  an  altitude  of  nearly  6,000 
feet,  and  the  center  of  motion  was  a  considerable  distance 
to  the  northwest,  where  it  must  have  reached  a  still  greater 
altitude. 

The  complete  similarity  of  the  conclusions  reached  by  four 
different  sets  of  observers  in  four  different  areas — Switzerland, 
northwestern  Europe,  the  British  Isles,  and  North  America — 
after  fifty  years  of  continuous  research,  and  after  every  other 
less  startling  theory  had  been  put  forth  and  rejected  as  wholly 
inconsistent  with  the  phenomena  to  be  explained,  renders  it  as 
certain  as  any  conclusion  from  indirect  evidence  can  be,  that  a 
large  portion  of  the  north  temperate  zone,  now  enjoying  a 
favorable  climate  and  occupied  by  the  most  civilized  nations  of 
the  world,  was,  at  a  very  recent  epoch,  geologically  speaking, 
completely  buried  in  ice,  just  as  Greenland  is  now.  How  re- 
cently the  ice  has  passed  away  is  shown  by  the  perfect  preser- 
vation of  innumerable  moraines,  perched  blocks,  erratics,  and 
glaciated  rock-surfaces,  showing  that  but  little  denudation  has 
occurred  to  modify  the  surface ;  while  undoubted  relics  of  man 
found  in  glacial  or  interglacial  deposits  prove  that  it  occurred 


GEOLOGY  isi 

during  the  human  period.  It  is  clear  that  man  could  not  have 
lived  in  any  area  while  it  was  actually  covered  by  the  ice-sheet, 
while  any  indications  of  his  presence  at  an  earlier  period  would 
almost  certainly  be  destroyed  by  the  enormous  abrading  and 
grinding  power  of  the  ice. 

Besides  the  areas  above  referred  to,  there  are  widespread 
indications  of  glaciation  in  parts  of  the  world  where  a  temperate 
climate  now  prevails.  In  the  Pyrenees,  Caucacus,  Lebanon, 
and  Himalayas  glacial  moraines  are  found  far  below  the  lower 
limits  they  now  attain.  In  the  Southern  Hemisphere  similar 
indications  are  found  in  New  Zealand,  Tasmania,  and  the  south- 
ern portion  of  the  Andes ;  but  whether  this  cold  period  was 
coincident  with  that  of  the  Northern  Hemisphere  we  have  at 
present  no  means  of  determining,  nor  even  whether  they  were 
coincident  among  themselves,  since  it  is  quite  conceivable  that 
they  may  have  been  due  to  local  causes,  such  as  greater  eleva- 
tion of  the  land,  and  not  to  any  general  cause  acting  through- 
out the  south  temperate  zone. 

In  the  north  temperate  zone,  however,  the  phenomena  are 
so  widespread  and  so  similar  in  character,  with  only  such  modi- 
fications as  are  readily  explained  by  proximity  to,  or  remoteness 
from,  the  ocean,  that  we  are  almost  sure  they  must  have  been 
simultaneous,  and  have  been  due  to  the  same  general  causes, 
though  perhaps  modified  by  local  changes  in  altitude  and  con- 
sequent modification  of  winds  or  ocean-currents.  The  time 
that  has  elapsed  since  the  glaciation  of  the  Northern  Hemis- 
phere passed  away  is,  geologically,  very  small  indeed,  and  has 
been  variously  estimated  at  from  20,000  to  100,000  years.  At 
present  the  smaller  period  is  most  favored  by  geologists,  but 
the  duration  of  the  ice  age  itself,  including  probably  one  or 
more  inter-glacial  mild  periods,  is  admitted  to  be  much  longer, 
and  probably  to  approach  the  higher  figure  above  given. 

The  undoubted  fact,  however,  that  a  large  part  of  the  north 
temperate  zone  has  been  recently  subjected  to  so  marvelous  a 
change  of  climate,  is  of  immense  interest  from  many  points  of 
view.  It  teaches  us  in  an  impressive  way  how  delicate  is  the 
balance  of  forces  which  renders  what  are  now  the  most  densely 
peopled  areas  habitable  by  man.  We  can  hardly  suppose  that 


188  ACHIEVEMENTS  IN  SCIENCE 

even  the  tremendously  severe  ice  age  of  which  we  have  evidence 
is  the  utmost  that  can  possibly  occur ;  and,  on  the  other  hand, 
we  may  anticipate  that  the  condition  of  things  which  in  earlier 
geological  times  rendered  even  the  polar  regions  adapted  for  a 
luxuriant  woody  vegetation  may  again  recur,  and  thus  vastly 
extend  the  area  of  our  globe  which  is  adapted  to  support  human 
life  in  abundance  and  comfort.  In  the  endeavor  to  account  for 
the  change  of  climate  and  of  physical  geography  which  brought 
about  so  vast  a  change,  and  then,  after  a  period  certainly  ap- 
proaching, and  perhaps  greatly  exceeding,  a  hundred  thousand 
years,  caused  it  to  pass  away,  some  of  the  most  acute  and 
powerful  intellects  of  our  day  have  exerted  their  ingenuity ; 
but,  so  far  as  obtaining  general  acceptance  for  the  views  of  any 
one  of  them,  altogether  in  vain.  There  seems  reason  to  be- 
lieve, however,  that  the  problem  is  not  an  insoluble  one ;  and 
when  the  true  cause  is  reached,  it  will  probably  carry  with  it 
the  long-sought  datum  from  which  to  calculate  with  some  rough 
degree  of  accuracy  the  duration  of  geological  periods.  But, 
whether  we  can  solve  the  problem  of  its  cause  or  no,  the  demon- 
stration of  the  recent  occurrence  of  a  Glacial  Epoch  or  Great 
Ice  Age,  with  the  determination  of  its  main  features  over  the 
Northern  Hemisphere,  will  ever  rank  as  one  of  the  great  scien- 
tific achievements  of  the  nineteenth  century. 

THE  ANTIQUITY  OF  MAN 

Following  the  general  acceptance  of  a  glacial  epoch  by 
about  twenty  years,  but  to  some  extent  connected  with  it,  came 
the  recognition  that  man  had  existed  in  Northern  Europe  along 
with  numerous  animals  which  no  longer  live  there — the  mam- 
moth, the  woolly  rhinoceros,  the  wild  horse,  the  cave-bear,  the 
lion,  the  sabre-toothed  tiger,  and  many  others — and  that  he 
had  left  behind  him,  in  an  abundance  of  rude  flint  implements, 
the  record  of  his  presence.  Before  that  time  geologists,  as  well 
as  the  whole  educated  world,  had  accepted  the  dogma  that  man 
appeared  upon  the  earth  only  when  both  its  physical  features 
and  its  animal  and  vegetable  forms  were  exactly  as  we  find 
them  to-day;  and  this  belief,  resting  solely  on  negative  evi- 


GEOLOGY  189 

dence,  was  so  strongly  and  irrationally  maintained  that  the 
earlier  discoveries  could  not  get  a  hearing.  A  careful  but 
enthusiatic  French  observer,  M.  Boucher  de  Perthes,  had  for 
many  years  collected  with  his  own  hands,  from  the  great 
deposits  of  old  river  gravels  in  the  valley  of  the  Somme  near 
Amiens,  abundance  of  large  and  well-formed  flint  implements. 
In  1847  he  published  an  account  of  them,  but  nobody  believed 
his  statements,  till,  ten  years  later,  Dr.  Falconer,  and  shortly 
afterward  Professor  Prestwich  and  Mr.  John  Evans,  examined 
the  collections  and  the  places  where  they  were  found,  and  were 
at  once  convinced  of  their  importance ;  and  their  testimony  led 
to  the  general  acceptance  of  the  great  antiquity  of  the  human 
race.  From  that  time  researches  on  this  subject  have  been 
carried  on  by  many  earnest  students,  and  have  opened  up  a 
number  of  altogether  new  chapters  in  human  history. 

So  soon  as  the  main  facts  were  established,  many  old 
records  of  similar  discoveries  were  called  to  mind,  all  of  which 
had  been  ignored  or  explained  away  on  account  of  the  strong 
prepossession  in  favor  of  the  very  recent  origin  of  man.  In 
1715  flint  weapons  had  been  found  in  excavations  near  Gray's 
Inn  Lane,  along  with  the  skeleton  of  an  elephant.  In  1800 
another  discovery  was  made  in  Suffolk  of  flint  weapons  and 
the  remains  of  extinct  animals  in  the  same  deposits.  In  1825 
Mr.  McEnery,  of  Torquay,  discovered  worked  flints  along  with 
the  bones  and  teeth  of  extinct  animals  in  Kent's  cavern.  In 
1 840  a  good  geologist  confirmed  these  discoveries,  and  sent  an 
account  of  them  to  the  Geological  Society  of  London,  but  the 
paper  was  rejected  as  being  too  improbable  for  publication! 
All  these  discoveries  were  laughed  at  or  explained  away,  as  the 
glacial  striae  and  grooves  so  beautifully  exhibited  in  the  Vale 
of  Llanberris  were  at  first  endeavored  to  be  explained  as  the 
wheel-ruts  caused  by  the  chariots  of  the  ancient  Britons! 
These,  combined  with  numerous  other  cases  of  the  denial  of 
facts  on  a  priori  grounds,  have  led  me  to  the  conclusion  that, 
whenever  the  scientific  men  of  any  age  disbelieve  other  men's 
careful  observations  without  inquiry,  the  scientific  men  are 
always  wrong. 

Even  after  these  evidences  of  man's  great  antiquity  were 


190  ACHIEVEMENTS  IN  SCIENCE 

admitted,  strenuous  efforts  were  made  to  minimize  the  time  as 
measured  by  years ;  and  it  was  maintained  that  man,  although 
undoubtedly  old,  was  entirely  post-glacial.  But  evidence  has 
been  steadily  accumulating  of  his  existence  at  the  time  of  the 
glacial  epoch,  and  even  before  it;  while  two  discoveries  of 
recent  date  seem  to  carry  back  his  age  far  into  pre-glacial  times. 
These  are,  first,  the  human  cranium,  bones,  and  works  of  art 
which  have  been  found  more  than  a  hundred  feet  deep  in  the 
gold-bearing  gravels  of  California,  associated  with  abundant 
vegetable  remains  of  extinct  species,  and  overlaid  by  four  suc- 
cessive lava  streams  from  long  extinct  volcanoes.  The  other 
case  is  that  of  rude  stone  implements  discovered  by  a  geologist 
of  the  Indian  Survey  in  Burma  in  deposits  which  are  admitted 
to  be  of  at  least  Pliocene  age.  In  both  these  cases  the  evidence 
is  disputed  by  some  geologists,  who  seem  to  think  that  there 
is  something  unscientific,  or  even  wrong,  in  admitting  evidence 
that  would  prove  the  Pliocene  age  of  any  other  animal  to  be 
equally  valid  in  the  case  of  man.  There  is  assumed  to  be  a 
great  improbability  of  his  existence  earlier  than  the  very  end 
of  the  Tertiary  epoch.  But  all  the  indications  drawn  from  his 
relations  to  the  anthropoid  apes  point  to  an  origin  far  back  in 
Tertiary  time.  For  each  one  of  the  great  apes— the  gorilla, 
the  chimpanzee,  the  orang,  and  even  the  gibbon — resemble 
man  in  certain  features  more  than  do  their  allies,  while  in  other 
points  they  are  less  like  him.  Now,  if  man  has  been  developed 
from  a  lower  animal  form,  we  must  seek  his  ancestors  not  in 
the  direct  line  between  him  and  any  of  the  apes,  but  in  a  line 
toward  a  common  ancestor  to  them  all ;  and  this  common  ances- 
tor must  certainly  date  back  to  the  early  part  of  the  Tertiary 
epoch,  because  in  the  Miocene  period  anthropoid  apes  not  very 
different  from  living  forms  have  been  found  fossil. 

There  is  therefore  no  improbability  whatever  in  the  exist- 
ence of  man  in  the  later  portions  of  the  Tertiary  period,  and 
we  have  no  right,  scientifically,  to  treat  any  evidence  for  his 
existence  in  any  other  way  than  the  evidence  for  the  existence 
of  other  animal  types. 

It  has  been  argued  by  some  writers  that,  as  no  other  living 
species  of  mammal  goes  back  farther  than  the  Newer  Pliocene, 


GEOLOGY  191 

therefore  man  is  probably  no  older.  But  it  is  forgotten  that 
the  difference  of  man  from  the  apes  is  not  only  specific  but  at 
least  of  generic  or  of  family  rank,  while  some  naturalists  place 
him  even  in  a  separate  order  of  mammalia.  Besides  the  erect 
posture  and  free  hands,  with  all  the  details  of  anatomical  struc- 
ture which  these  peculiarities  imply,  the  great  development  of 
his  brain  pre-eminently  distinguishes  him.  We  may  suppose, 
therefore,  that  when  he  had  reached  the  erect  form,  and  pos- 
sessed all  the  external  appearance  of  man,  his  brain  still  re- 
mained undeveloped,  and  the  time  occupied  by  this  develop- 
ment was  not  improbably  equal  to  that  required  for  the  specific 
modification  of  the  lower  mammalia.  It  is  often  forgotten  that 
so  soon  as  man  used  fire  and  made  weapons,  all  further  useful 
modification  would  be  in  the  direction  of  increased  brain  power, 
by  which  he  was  able  to  succeed  both  in  his  struggle  against 
the  elements  and  with  the  lower  animals.  There  is  therefore 
no  improbability  in  finding  the  remains  or  the  implements  of 
a  low  type  of  man  in  the  early  Pliocene  period. 

The  certainty  that  man  coexisted  with  many  now  extinct 
animals,  and  the  probability  of  our  discovering  his  remains  in 
undoubted  Tertiary  strata,  constitute  an  immense  advance  on 
the  knowledge  and  beliefs  of  our  forefathers,  and  must  there- 
fore rank  among  the  prominent  features  in  the  scientific  prog- 
ress of  the  nineteenth  century. 


GEOLOGY 
Coal 

By  ELISHA  GRAY 

LONG  ago,  some  man  made  the  discovery  that  what  we  now 
call  coal  would  burn  and  produce  light  and  warmth.  Who 
he  was  or  how  long  ago  he  lived  we  do  not  know,  but  as  all 
earthly  things  have  a  beginning,  we  know  that  such  a  man  did 
live  and  that  the  discovery  that  coal  would  burn  was  made. 
Coal,  in  the  sense  that  we  use  the  word  here,  is  not  mentioned 
in  the  Scriptures.  According  to  some  authorities,  coal  was 
used  in  England  as  early  as  the  ninth  century.  It  is  recorded 
that  in  1259  King  Henry  III.  granted  a  privilege  to  certain 
parties  to  mine  coal  at  Newcastle.  It  is  further  stated  that 
seven  years  after  this  time  coal  became  an  article  of  export. 
In  1306,  coal  was  so  generally  used  in  London  that  a  petition 
was  sent  to  Parliament  to  have  the  use  of  it  suppressed  on  the 
ground  that  it  was  a  nuisance.  Coal  was  used  in  Belgium, 
however,  about  1200.  There  is  a  tradition  that  a  blacksmith 
first  used  it  in  Liege  as  fuel.  It  was  first  used  for  manufac- 
turing purposes  about  1713. 

Coal  is  found  laid  down  in  great  veins,  varying  in  thickness, 
in  various  parts  of  the  world  in  the  upper  strata  of  the  Paleozoic 
era.  The  age  in  which  it  was  formed  is  called  by  geologists 
the  Carboniferous  (coal-bearing)  age. 

Before  going  on  to  account  for  the  deposits  of  coal,  let  us 
stop  a  moment  and  consider  what  it  is.  Chemists  tell  us  that 
coal  is  constructed  chiefly  of  carbon,  compounded  with  oxygen, 
hydrogen,  and  nitrogen.  There  are  many  varieties,  but  all 
may  be  classified  under  two  general  headings — bituminous  and 

192 


GEOLOGY  193 

anthracite.  Bituminous  coal  contains  a  large  amount  of  a 
tarry  substance,  a  kind  of  mineral  pitch  or  bitumen,  which 
burns  with  a  brilliant  flame  and  a  black  sooty  smoke,  exceed- 
ingly rich  in  carbon.  Anthracite  coal  is  hard  and  stone-like  in 
its  texture,  burning  with  scarcely  any  flame  and  no  smoke.  It 
produces  a  fire  of  intense  heat  when  it  is  once  ignited.  There 
is  another  form  of  coal  called  cannel  coal,  which  is  a  corruption 
of  "candle  coal,"  so  called  because  a  piece  of  this  kind  of  coal 
when  ignited  will  burn  like  a  match  or  pine  knot  and  give  light 
like  a  candle.  This  is  the  richest  of  all  the  coal  deposits  in 
gases  that  are  set  free  by  heat,  and  for  this  reason  is  extensively 
used  in  the  manufacture  of  what  is  commonly  called  coal  gas. 
England  produces  a  large  amount  of  cannel  coal,  as  well  as 
another  variety  of  bituminous  coal,  which  latter,  however,  does 
not  burn  with  such  a  black  smoke  as  the  coal  found  in  the  Ohio 
valley  and  the  Western  States  of  America.  East  of  the  Alle- 
ghany  Mountains  there  is  a  region  of  anthracite  coal  that  is 
very  extensively  worked  and  finds  great  favor  in  all  parts  of 
the  country  as  fuel  for  domestic  heating,  especially  on  account 
of  its  great  cleanliness. 

All  of  the  coal  beds  have  a  common  origin,  and  the  differ- 
ence in  the  quality  of  coal  found  in  different  parts  of  the  coun- 
try is  due  to  many  circumstances,  some  of  which  have  never 
been  explained.  There  is  indisputable  proof,  however,  that  all 
coal  beds  are  of  vegetable  origin.  Geologists  tell  us  that  these 
coal  beds  were  formed  during  an  age  before  the  earth  had 
cooled  down  to  the  temperature  that  it  has  at  the  present  time 
—an  age  when  vegetation  was  forced  by  the  internal  heat  of 
the  earth,  instead  of  having  to  receive  all  its  warmth  from  the 
m's  rays  as  we  do  now.  Some  of  our  readers  are  familiar 
dth  what  is  commonly  termed  a  hot-bed.  A  hot-bed  is  made 
putting  soil  on  top  of  substances  that  will  ferment  and 
reate  heat  underneath  the  soil.  This  heat  from  beneath  will 
force  vegetation  and  cause  a  much  larger  growth  than  there 
will  be  if  left  to  the  sun's  rays  alone.  During  the  carbonifer- 
ous age  the  earth  was  a  great  hot-bed. 

The  fossils  of  trees  and  plants,  as  well  as  reptiles,  that  we 
in  the  great  coal  measures  of  the  world,  show  that  they 
13 


194  ACHIEVEMENTS  IN  SCIENCE 

were  of  large  tropical  growth,  and  this  is  shown  not  only  in  the 
temperate  zone,  but  in  the  zone  farther  north.  For  ages  and 
ages  this  rank  growth  of  vegetation  grew  up  and  fell  down  until 
a  great  layer  of  vegetable  matter  was  formed,  which  at  a  later 
time  was  covered  over  by  other  strata  of  varied  earth  material, 
so  that  these  great  layers  of  vegetable  formation  were  hermeti- 
cally sealed  and  pressed  down  by  an  enormous  weight  that 
increased  as  time  went  on.  The  formation  of  coal  may  be 
studied  even  at  this  day  (for  it  is  now  going  on)  by  visiting  and 
examining  the  great  peat  beds  that  are  found  in  various  parts 
of  the  world.  It  is  well  known  that  peat  is  used  as  a  fuel  by 
many  people,  especially  the  peasantry  of  the  old  countries.  If 
peat  is  pressed  to  a  sufficient  degree  of  hardness  it  burns  in  a 
manner  not  unlike  some  forms  of  coal.  Peat  is  a  vegetable 
formation  and  has  been  formed  by  the  rank  growth  of  various 
kinds  of  vegetation  in  swampy  places.  Of  course,  it  lacks  the 
purity  of  the  coal  that  was  formed  during  the  carboniferous 
age,  because  of  the  much  slower  growth  of  vegetation  now  than 
during  that  time,  and  the  opportunity  that  peat  bogs  offer  for 
an  intermixture  of  earthy  with  the  vegetable  matter.  The  fact 
that  we  find  the  imprint  of  trees  and  ferns  and  other  vegetable 
growth  of  tropical  varieties,  as  well  as  the  fossils  of  reptiles, 
imbedded  in  the  coal  measures,  proves  that  at  one  time  this 
stratum  was  at  the  land  surface  of  the  earth.  We  also  find 
that  all  the  formations  of  the  Secondary  and  Tertiary  periods 
are  on  top  of  the  coal — and  this  shows  that  after  the  age  of 
rank  vegetable  growth  there  was  a  sinking  of  the  earth  in  many 
places  far  down  into  the  ocean — so  that  vast  layers  of  rock 
formed  on  top  of  these  beds  of  vegetable  matter.  In  England 
great  chalk  beds  crop  out  in  cliffs  on  the  southern  coast,  and 
these  chalk  rocks  are  made  up  largely  of  the  shells  of  marine 
animals.  London  stands  on  a  chalk  bed,  from  six  hundred  to 
eight  hundred  feet  thick.  Indeed,  England  has  been  poetically 
called  Albion,  White-land,  from  this  appearance  of  her  coast. 

All  of  the  great  chalk  beds  were  formed  ages  after  the  coal 
beds,  as  the  latter  are  found  in  the  upper  strata  of  the  Paleozoic 
period. 

A  study  of  these  strata  will  show  that  there  are  many  layers 


GEOLOGY  195 

of  coal  strata  varying  in  thickness  and  separated  by  layers  of 
shale  and  sandstone. 

From  the  position  that  the  coal  measures  occupy,  being 
entirely  under  the  Secondary  and  Tertiary  formations,  it  will 
be  observed  that  they  are  very  old.  If  we  should  examine  a 
piece  of  ordinary  bituminous  coal  we  shoud  find  that  there  are 
lines  of  cleavage  in  it  parallel  to  each  other,  and  that  it  is  an 
easy  matter  to  separate  the  lump  on  these  lines.  If  we  exam- 
ine the  outcrop  of  a  coal  bed  we  shall  find  that  these  lines  of 
cleavage  are  horizontal.  This  indicates  that  the  great  bulk  of 
vegetable  matter  of  which  the  coal  formation  is  made  up  has 
been  subjected  to  tremendous  pressure  during  a  long  period  of 
time.  If  we  further  examine  the  structure  of  a  body  of  coal 
we  find  the  impressions  of  limbs  and  branches  as  well  as  the 
leaves  of  trees  and  various  kinds  of  plants.  We  shall  further 
find  that  these  impressions  lie  in  a  plane  in  the  same  direction 
as  the  line  of  cleavage.  This  is  a  point  to  be  remembered,  as 
it  helps  to  explain  the  nature  and  structure  of  other  formations 
than  those  of  coal.  Not  only  are  leaves  and  branches  of  vege- 
table matter  found,  but  also  fossils  of  reptiles,  such  as  live  on 
the  land.  Sometimes  there  is  found  the  fossil  of  a  great  tree 
trunk  standing  in  an  erect  position,  with  its  roots  running  down 
into  the  rock  below  the  coal  bed,  while  the  trunk  extends  up- 
ward entirely  through  the  coal  and  high  up  into  the  other 
strata.  All  of  these  facts  lead  us  to  the  firm  conclusion  that 
when  the  trees  were  grown  that  formed  these  beds,  they  were 
above  the  surface  of  the  ocean.  This,  taken  in  connection  with 
the  fact  that  the  vegetable  fossils  that  are  found  indicate  a 
tropical  growth  of  great  size,  leads  to  the  conclusion  that  the 
climate  at  the  time  these  coal  measures  were  formed  was  much 
warmer  than  it  is  now. 

As  already  remarked,  this  extra  warmth  came  from  the 
earth  itself  before  it  had  cooled  down  to  its  present  tempera- 
ture, rather  than  from  the  heat  of  the  sun.  There  is  nothing 
inconsistent  in  the  thought  that  the  sun  may  have  been  warmer 
in  a  former  age  than  now.  We  may  conceive  that  the  earliest 
coal  formations  took  place  when  the  land  stood  above  the  sur- 
face of  the  water,  and  that  the  conditions  were  favorable  for  a 


196  ACHIEVEMENTS  IN  SCIENCE 

rapid  and  luxuriant  growth  of  vegetation ;  after  this  had  gone 
on  for  a  very  long  period  of  time,  by  some  convulsion  of  nature 
the  land  surface  was  submerged  under  the  ocean,  when  other 
mineral  substances  were  deposited  on  top  of  this  layer  of  vege- 
table growth,  which  hardened  into  a  rock  formation.  At  a 
later  period  the  earth  was  again  elevated  above  the  surface  of 
the  water  and  the  same  process  of  growth  and  decay  was  re- 
peated. These  oscillations  of  the  earth  up  and  down  occurred 
at  enormously  long  intervals,  until  all  of  the  various  coal  strata 
with  their  intermediate  formations  were  completed.  After  this 
we  must  suppose  that  the  whole  was  submerged  to  a  great 
depth  and  for  a  very  long  period  of  time,  because  of  the  great 
number  and  various  kinds  of  rock  formations  laid  down  by 
water  that  lie  on  top  of  the  coal  measures.  This  tremendous 
weight,  as  it  was  gradually  builded  up,  subjected  these  vegeta- 
ble strata  to  an  inconceivable  pressure.  In  some  places  this 
pressure  was  much  greater  than  in  others,  which  undoubtedly 
is  one  of  the  reasons  why  we  find  such  differences  in  the  struc- 
ture and  quality  of  coal.  There  were,  no  doubt,  many  other 
reasons  for  differences,  one  of  them  being  the  character  of  the 
vegetable  growth  out  of  which  they  were  formed.  Again,  in 
some  parts  of  the  world  these  coal  strata  may  have  been  sub- 
jected to  a  considerable  degree  of  heat,  which  would  change 
the  structure  of  the  formation,  and  in  some  cases  drive  off  the 
volatile  gases.  One  can  easily  imagine  that  heat  was  thus  a 
factor  in  the  formation  of  what  is  known  as  anthracite  coal,  so 
much  less  gaseous  than  the  bituminous  kinds.  The  anthra- 
cite beds  seem  to  be  denser  and  of  a  more  homogeneous  char- 
acter. The  lines  of  cleavage  are  not  so  prominent,  but  there 
are  the  same  evidences  of  vegetable  origin  that  we  find  in  the 
bituminous  formations. 

It  will  be  seen  from  what  has  gone  before  that  coal  was 
first  wood.  But  wood  is  a  product  of  sunshine.  Thus  the  sun 
was  the  architect  and  builder  of  the  trees  and  plants  that  were 
finally  hermetically  sealed  under  the  great  earth  strata.  The 
sun  gathered  up  the  material  and  set  in  play  the  forces  which 
made  the  chemical  combinations  of  the  various  elements  in 
nature  that  enter  into  vegetable  growth. 


GEOLOGY 


197 


After  the  lapse  of  untold  ages  of  time,  these  great  beds  of 
stored-up  sun-energy  were  discovered  by  man  and  their  con- 
tents were  dragged  out  to  the  earth's  surface,  to  warm  our 
houses,  to  drive  the  machinery  of  our  factories,  to  send  the 
locomotives  flying  across  the  continents  and  the  steamships 
over  the  oceans.  So  important  has  this  article  become  that  if 
any  one  nation  could  control  the  output  it  would  be  able  to 
paralyze  all  the  navies  and  the  manufacturing  of  the  world. 

If  the  coal  of  the  world  should  become  exhausted  we  should 
be  confronted  with  a  great  problem.  Fortunately  for  us,  this 
is  a  problem  that  will  have  to  be  solved  by  the  people  of  some 
future  age,  as  the  growth  of  wood  will  scarcely  keep  pace  with 
the  consumption  of  fuel.  By  that  time  the  genius  of  man  will 
have  devised  an  economical  means  of  storing  the  energy  of  the 
sunbeams  directly  for  purposes  of  heat,  light,  and  power. 


GEOLOGY 
On  a  Piece  of  Chalk 

By  T.  H.  HUXLEY 

IF  a  well  were  to  be  sunk  at  our  feet  in  the  midst  of  the  Eng- 
lish city  of  Norwich,  the  diggers  would  very  soon  find 
themselves  at  work  in  that  white  substance  almost  too  soft  to 
be  called  rock,  with  which  we  are  all  familiar  as  "  chalk." 

Not  only  here,  but  over  the  whole  county  of  Norfolk,  the 
well-sinker  might  carry  his  shaft  down  many  hundred  feet 
without  coming  to  the  end  of  the  chalk ;  and,  on  the  sea-coast, 
where  the  waves  have  pared  away  the  face  of  the  land  which 
breasts  them,  the  scarped  faces  of  the  high  cliffs  are  often 
wholly  formed  of  the  same  material.  Northward,  the  chalk 
may  be  followed  as  far  as  Yorkshire ;  on  the  south  coast  it  ap- 
pears abruptly  in  the  picturesque  western  bays  of  Dorset,  and 
breaks  into  the  Needles  of  the  Isle  of  Wight ;  while  on  the 
shores  of  Kent  it  supplies  that  long  line  of  white  cliffs  to  which 
England  owes  her  name  of  Albion. 

Were  the  thin  soil  which  covers  it  all  washed  away,  a  curved 
band  of  white  chalk,  here  broader  and  there  narrower,  might 
be  followed  diagonally  across  England  from  Lulworth  in  Dor- 
set, to  Flamborough  Head  in  Yorkshire — a  distance  of  over 
two  hundred  and  eighty  miles  as  the  crow  flies. 

From  this  band  to  the  North  Sea,  on  the  east,  and  -tie 
Channel,  on  the  south,  the  chalk  is  largely  hidden  by  other  de- 
posits ;  but,  except  in  the  Weald  of  Kent  and  Sussex,  it  enters 
into  the  very  foundation  of  all  the  southeastern  counties. 

Attaining,  as  it  does  in  some  places,  a  thickness  more  of 

198 


GEOLOGY  199 

than  a  thousand  feet,  the  English  chalk  must  be  admitted  to  be 
a  mass  of  considerable  magnitude.  Nevertheless,  it  covers  but 
an  insignificant  portion  of  the  whole  area  occupied  by  the  chalk 
formation  of  the  globe,  which  has  precisely  the  same  general 
character  as  ours,  and  is  found  in  detached  patches,  some  less, 
and  others  more  extensive,  than  the  English. 

Chalk  occurs  in  Northwest  Ireland;  it  stretches  over  a 
large  part  of  France — the  chalk  which  underlies  Paris  being,  in 
fact,  a  continuation  of  that  of  the  London  basin;  it  runs 
through  Denmark  and  Central  Europe,  and  extends  southward 
to  North  Africa ;  while  eastward,  it  appears  in  the  Crimea  and 
in  Syria,  and  may  be  traced  as  far  as  the  shores  of  the  Sea  of 
Aral,  in  Central  Asia. 

If  all  the  points  at  which  true  chalk  occurs  were  circum- 
scribed, they  would  lie  within  an  irregular  oval  about  three 
thousand  miles  in  long  diameter — the  area  of  which  would  be 
as  great  as  that  of  Europe,  and  would  many  times  exceed  that 
of  the  largest  existing  inland  sea — the  Mediterranean. 

Thus  the  chalk  is  no  unimportant  element  in  the  masonry 
of  the  earth's  crust,  and  it  impresses  a  peculiar  stamp,  varying 
with  the  conditions  to  which  it  is  exposed,  on  the  scenery  of 
the  districts  in  which  it  occurs.  The  undulating  downs  and 
rounded  coombs,  covered  with  sweet-grassed  turf,  of  our  inland 
:halk  country,  have  a  peacefully  domestic  and  mutton-suggest- 
ig  prettiness,  but  can  hardly  be  called  either  grand  or  beauti- 
il.  But  on  our  southern  coasts,  the  wall-sided  cliffs,  many 
nmdred  feet  high,  with  vast  needles  and  pinnacles  standing 
out  in  .the  sea,  sharp  and  solitary  enough  to  serve  as  perches 
for  the  wary  cormorant,  confer  a  wonderful  beauty  and  grand- 
iur  upon  the  chalk  headlands.  And  in  the  East,  chalk  has 
its  share  in  the  formation  of  some  of  the  most  venerable  of 
lountain  ranges,  such  as  the  Lebanon. 

What  is  this  widespread  component  of  the  surface  of  the 
earth  ?  and  whence  did  it  come  ? 

You  may  think  this  no  very  hopeful  inquiry.     You  may  not 
innaturally  suppose  that  the  attempt  to  solve  such  problems 
these  can  lead  to  no  result,  save  that  of  entangling  the 


200  ACHIEVEMENTS  IN  SCIENCE 

inquirer  in  vague  speculations,  incapable  of  refutation  and  of 
verification. 

If  such  were  really  the  case,  I  should  have  selected  some 
other  subject  than  "a  piece  of  chalk  "  for  my  discourse.  But, 
in  truth,  after  much  deliberation,  I  have  been  unable  to  think 
of  any  topic  which  would  so  well  enable  me  to  lead  you  to  see 
how  solid  is  the  foundation  upon  which  some  of  the  most  start- 
ling conclusions  of  physical  science  rest. 

A  great  chapter  of  the  history  of  the  world  is  written  in  the 
chalk.  Few  passages  in  the  history  of  man  can  be  supported 
by  such  an  overwhelming  mass  of  direct  and  indirect  evidence 
as  that  which  testifies  to  the  truth  of  the  fragment  of  the  his- 
tory of  the  globe,  which  I  hope  to  enable  you  to  read,  with 
your  own  eyes,  to-night. 

Let  me  add,  that  few  chapters  of  human  history  have  a 
more  profound  significance  for  ourselves.  I  weigh  my  words 
well  when  I  assert,  that  the  man  who  should  know  the  true 
history  of  the  bit  of  chalk  which  every  carpenter  carries  about 
in  his  breeches'  pocket,  though  ignorant  of  all  other  history,  is 
likely,  if  he  will  think  his  knowledge  out  to  its  ultimate  results, 
to  have  a  truer,  and  therefore  a  better,  conception  of  this  won- 
derful universe,  and  of  man's  relation  to  it,  than  the  most 
learned  student  who  is  deep-read  in  the  records  of  humanity 
and  ignorant  of  those  of  nature. 

The  language  of  the  chalk  is  not  hard  to  learn,  not  nearly 
so  hard  as  Latin,  if  you  only  want  to  get  at  the  broad  features 
of  the  story  it  has  to  tell ;  and  I  propose  that  we  now  set  to 
work  to  spell  that  story  out  together. 

We  all  know  that  if  we  "  burn  "  chalk,  the  result  is  quick- 
lime. Chalk,  in  fact,  is  a  compound  of  carbonic  acid  gas  and 
lime ;  and  when  you  make  it  very  hot,  the  carbonic  acid  flies 
away  and  the  lime  is  left. 

By  this  method  of  procedure  we  see  the  lime,  but  we  do  not 
see  the  carbonic  acid.  If,  on  the  other  hand,  you  were  to  pow- 
der a  little  chalk  and  drop  it  into  a  good  deal  of  strong  vinegar, 
there  would  be  a  great  bubbling  and  fizzing,  and  finally  a  clear 
liquid,  in  which  no  sign  of  chalk  would  appear.  Here  you  see 
the  carbonic  acid  in  the  bubbles;  the  lime,  dissolved  in  the 


THOMAS  H.  HUXLEY. 


.GEOLOGY  201 

vinegar,  vanishes  from  sight.  There  are  a  great  many  other 
ways  of  showing  that  chalk  is  essentially  nothing  but  carbonic 
acid  and  quicklime.  Chemists  enunciate  the  result  of  all  the 
experiments  which  prove  this,  by  stating  that  chalk  is  almost 
wholly  composed  of  "  carbonate  of  lime." 

It  is  desirable  for  us  to  start  from  the  knowledge  of  this 
fact,  though  it  may  not  seem  to  help  us  very  far  toward  what 
we  seek.  For  carbonate  of  lime  is  a  widely  spread  substance, 
and  is  met  with  under  very  various  conditions.  All  sorts  of 
limestones  are  composed  of  more  or  less  pure  carbonate  of 
lime.  The  crust  which  is  often  deposited  by  waters  which 
have  drained  through  limestone  rocks,  in  the  form  of  what  are 
called  stalagmites  and  stalactites,  is  carbonate  of  lime.  Or,  to 
take  a  more  familiar  example,  the  fur  on  the  inside  of  a  tea- 
kettle is  carbonate  of  lime ;  and,  for  anything  chemistry  tells 
us  to  the  contrary,  the  chalk  might  be  a  kind  of  gigantic  fur 
upon  the  bottom  of  the  earth-kettle,  which  is  kept  pretty  hot 
below. 

Let  us  try  another  method  of  making  the  chalk  tell  us  its 
m  history.  To  the  unassisted  eye  chalk  looks  simply  like  a 
;ry  loose  and  open  kind  of  stone.  But  it  is  possible  to  grind 
slice  of  chalk  down  so  thin  that  you  can  see  through  it — until 
is  thin  enough,  in  fact,  to  be  examined  with  any  magnifying 
>wer  that  may  be  thought  desirable  A  thin  slice  of  the  fur 
a  kettle  might  be  made  in  the  same  way.  If  it  were  exam- 
icd  microscopically,  it  would  show  itself  to  be  a  more  or  less 
istinctly  laminated  mineral  substance,  and  nothing  more. 

But  the  slice  of  chalk  presents  a  totally  different  appearance 
fhen  placed  under  the  microscope.    The  general  mass  of  it  is 
lade  up  of  very  minute  granules ;  but  imbedded  in  this  matrix 
are  innumerable  bodies,  some  smaller  and  some  larger,  but,  on 
a  rough  average,  not  more  than  a  hundredth  of  an  inch  in  di- 
ameter, having  a  well-defined  shape  and  structure.    A  cubic 
inch  of  some  specimens  of  chalk  may  contain  hundreds  of  thou- 
sands of  these  bodies,  compacted  together  with  incalculable 
lillions  of  the  granules. 

The  examination  of  a  transparent  slice  gives  a  good  notion 
the  manner  in  which  the  components  of  the  chalk  are 


202  ACHIEVEMENTS  IN  SCIENCE 

arranged,  and  of  their  relative  proportions.  But,  by  rubbing  up 
some  chalk  with  a  brush  in  water  and  then  pouring  off  the 
milky  fluid,  so  as  to  obtain  sediments  of  different  degrees  of 
fineness,  the  granules  and  the  minute  rounded  bodies  may  be 
pretty  well  separated  from  one  another,  and  submitted  to  mi- 
croscopic examination,  either  as  opaque  or  as  transparent  ob- 
jects. By  combining  the  views  obtained  in  these  various 
methods,  each  of  the  rounded  bodies  may  be  proved  to  be  a 
beautifully  constructed  calcareous  fabric,  made  up  of  a  number 
of  chambers,  communicating  freely  with  one  another.  The 
chambered  bodies  are  of  various  forms.  One  of  the  common- 
est is  something  like  a  badly  grown  raspberry,  being  formed 
of  a  number  of  nearly  globular  chambers  of  different  sizes  con- 
gregated together.  It  is  called  Globigerina,  and  some  speci- 
mens of  chalk  consist  of  little  else  than  Globigerinae  and 
granules. 

Let  us  fix  our  attention  upon  the  Globigerina.  If  we  can 
learn  what  it  is  and  what  are  the  conditions  of  its  existence, 
we  shall  see  our  way  to  the  origin  and  past  history  of  the  chalk. 

A  suggestion  which  may  naturally  enough  present  itself  is, 
that  these  curious  bodies  are  the  result  of  some  process  of 
aggregation  which  has  taken  place  in  the  carbonate  of  lime ; 
that,  just  as  in  winter,  the  rime  on  our  windows  simulates  the 
most  delicate  and  elegantly  arborescent  foliage — proving  that 
the  mere  mineral  matter  may,  under  certain  conditions,  assume 
the  outward  form  of  organic  bodies — so  this  mineral  substance, 
carbonate  of  lime,  hidden  away  in  the  bowels  of  the  earth,  has 
taken  the  shape  of  these  chambered  bodies.  I  am  not  raising 
a  merely  fanciful  and  unreal  objection.  Very  learned  men,  in 
former  days,  have  even  entertained  the  notion  that  all  the 
formed  things  found  in  rocks  are  of  this  nature ;  and  if  no  such 
conception  is  at  present  held  to  be  admissible,  it  is  because 
long  and  varied  experience  has  now  shown  that  mineral  matter 
never  does  assume  the  form  and  structure  we  find  in  fossils. 
If  any  one  were  to  try  to  persuade  you  that  an  oyster-shell 
(which  is  also  chiefly  composed  of  carbonate  of  lime)  had  crys- 
tallized out  of  sea-water,  I  suppose  you  would  laugh  at  the  ab- 
surdity. Your  laughter  would  be  justified  by  the  fact  that  all 


GEOLOGY  203 

experience  tends  to  show  that  oyster-shells  are  formed  by  the 
agency  of  oysters,  and  in  no  other  way.  And  if  there  were  no 
better  reasons,  we  should  be  justified,  on  like  grounds,  in  be- 
lieving that  Globigerina  is  not  the  product  of  anything  but 
vital  activity. 

Happily,  however,  better  evidence  in  proof  of  the  organic 
nature  of  the  Globigerinse  than  that  of  analogy  is  forthcoming. 
It  so  happens  that  calcareous  skeletons,  exactly  similar  to  the 
Globigerinae  of  the  chalk,  are  being  formed,  at  the  present 
moment,  by  minute  living  creatures,  which  flourish  in  multi- 
tudes, literally  more  numerous  than  the  sands  of  the  seashore, 
over  a  large  extent  of  that  part  of  the  earth's  surface  which  is 
covered  by  the  ocean. 

The  history  of  the  discovery  of  these  living  Globigerinae, 
and  of  the  part  which  they  play  in  rock-building,  is  singular 
enough.  It  is  a  discovery  which,  like  others  of  no  less  scien- 
tific importance,  has  arisen,  incidentally,  out  of  work  devoted 
to  very  different  and  exceedingly  practical  interests. 

When  men  first  took  to  the  sea,  they  speedily  learned  to 
look  out  for  shoals  and  rocks ;  and  the  more  the  burden  of  their 
ships  increased,  the  more  imperatively  necessary  it  became  for 
sailors  to  ascertain  with  precision  the  depth  of  the  waters  they 
traversed.  Out  of  this  necessity  grew  the  use  of  the  lead  and 
sounding-line ;  and,  ultimately,  marine  surveying,  which  is  the 
recording  of  the  form  of  coasts  and  of  the  depth  of  the  sea,  as 
ascertained  by  the  sounding-lead,  upon  charts. 

At  the  same  time,  it  became  desirable  to  ascertain  and  to 
indicate  the  nature  of  the  sea-bottom,  since  this  circumstance 
greatly  affects  its  goodness  as  holding  ground  for  anchors. 
Some  ingenious  tar,  whose  name  deserves  a  better  fate  than 
the  oblivion  into  which  it  has  fallen,  attained  this  object  by 
"arming"  the  bottom  of  the  lead  with  a  lump  of  grease,  to 
which  more  or  less  of  the  sand  or  mud,  or  broken  shells,  as  the 
case  might  be,  adhered,  and  was  brought  to  the  surface.  But, 
however  well  adapted  such  an  apparatus  might  be  for  rough 
nautical  purposes,  scientific  accuracy  could  not  be  expected 
from  the  armed  lead,  and  to  remedy  its  defects  (especially  when 
applied  to  sounding  in  great  depths)  Lieutenant  Brooke,  of  the 


204  ACHIEVEMENTS  IN  SCIENCE 

American  Navy,  some  years  ago  invented  a  most  ingenious 
machine,  by  which  a  considerable  portion  of  the  superficial 
layer  of  the  sea-bottom  can  be  scooped  out  and  brought  up 
from  any  depth  to  which  the  lead  descends. 

In  1853,  Lieutenant  Brooke  obtained  mud  from  the  bottom 
of  the  North  Atlantic,  between  Newfoundland  and  the  Azores, 
at  a  depth  of  more  than  10,000  feet,  or  two  miles,  by  the  help 
of  this  sounding  apparatus.  The  specimens  were  sent  for 
examination  to  Ehrenberg  of  Berlin,  and  to  Bailey  of  West 
Point,  and  those  able  microscopists  found  that  this  deep-sea 
mud  was  almost  entirely  composed  of  the  skeletons  of  living 
organisms — the  greater  proportion  of  these  being  just  like  the 
Globigerinse  already  known  to  occur  in  chalk. 

Thus  far,  the  work  had  been  carried  on  simply  in  the  inter- 
ests of  science,  but  Lieutenant  Brooke's  method  of  sounding 
acquired  a  high  commercial  value  when  the  enterprise  of  lay- 
ing down  the  telegraph-cable  between  this  country  and  the 
United  States  was  undertaken.  For  it  became  a  matter  of 
immense  importance  to  know,  not  only  the  depth  of  the  sea 
over  the  whole  line  along  which  the  cable  was  to  be  laid,  but 
the  exact  nature  of  the  bottom,  so  as  to  guard  against  chances 
of  cutting  or  fraying  the  strands  of  that  costly  rope.  The  Ad- 
miralty consequently  ordered  Captain  Dayman,  an  old  friend 
and  shipmate  of  mine,  to  ascertain  the  depth  over  the  whole 
line  of  the  cable,  and  to  bring  back  specimens  of  the  bottom. 
In  former  days,  such  a  command  as  this  might  have  sounded 
very  much  like  one  of  the  impossible  things  which  the  young 
prince  in  the  fairy  tales  is  ordered  to  do  before  he  can  obtain 
the  hand  of  the  princess.  However,  in  the  months  of  June 
and  July,  1857,  my  friend  performed  the  task  assigned  to  him 
with  great  expedition  and  precision,  without,  so  far  as  I  know, 
having  met  with  any  reward  of  that  kind.  The  specimens  of 
Atlantic  mud  which  he  procured  were  sent  to  me  to  be  exam- 
ined and  reported  upon. 

The  result  of  all  these  operations  is,  that  we  know  the  con- 
tours and  the  nature  of  the  surface-soil  covered  by  the  North 
Atlantic,  for  a  distance  of  1,700  miles  from  east  to  west,  as  well 
as  we  know  that  of  any  part  of  the  dry  land. 


GEOLOGY  205 

It  is  a  prodigious  plain — one  of  the  widest  and  most  even 
plains  in  the  world.  If  the  sea  were  drained  off,  you  might 
drive  a  wagon  all  the  way  from  Valentia,  on  the  west  coast  of 
Ireland,  to  Trinity  Bay  in  Newfoundland.  And,  except  upon 
one  sharp  incline  about  two  hundred  miles  from  Valentia,  I  am 
not  quite  sure  that  it  would  even  be  necessary  to  put  the  skid 
on,  so  gentle  are  the  ascents  and  descents  upon  that  long  route. 
From  Valentia  the  road  would  lie  down-hill  for  about  two  hun- 
dred miles  to  the  point  at  which  the  bottom  is  now  covered  by 
1,700  fathoms  of  sea-water.  Then  would  come  the  central 
plain,  more  than  a  thousand  miles  wide,  the  inequalities  of  the 
surface  of  which  would  be  hardly  perceptible,  though  the  depth 
of  water  upon  it  now  varies  from  10,000  to  15,0^0  feet;  and 
there  are  places  in  which  Mont  Blanc  might  be  sunk  without 
showing  its  peak  above  water.  Beyond  this,  the  ascent  on  the 
American  side  commences,  and  gradually  leads,  for  about  three 
hundred  miles,  to  the  Newfoundland  shore. 

Almost  the  whole  of  the  bottom  of  this  central  plain  (which 
extends  for  many  hundred  miles  in  a  north  and  south  direction) 
is  covered  by  a  fine  mud,  which,  when  brought  to  the  surface, 
dries  into  a  grayish  white  friable  substance.  You  can  write 
with  this  on  a  blackboard,  if  you  are  so  inclined;  and,  to  the 
eye,  it  is  quite  like  very  soft,  grayish  chalk.  Examined  chemi- 
cally, it  proves  to  be  composed  almost  wholly  of  carbonate  of 
lime ;  and  if  you  make  a  section  of  it,  in  the  same  way  as  that 
of  the  piece  of  chalk  was  made,  and  view  it  with  the  micro- 
scope, it  presents  innumerable  Globigerinse  embedded  in  a 
granular  matrix. 

Thus  this  deep-sea  mud  is  substantially  chalk.  I  say  sub- 
stantially, because  there  are  a  good  many  minor  differences ; 
but  as  these  have  no  bearing  on  the  question  immediately  be- 
fore us — which  is  the  nature  of  the  Globigerinae  of  the  chalk — 
it  is  unnecessary  to  speak  of  them. 

Globigerinae  of  every  size,  from  the  smallest  to  the  largest, 
are  associated  together  in  the  Atlantic  mud,  and  the  chambers 
of  many  are  filled  by  a  soft  animal  matter.  This  soft  substance 
is,  in  fact,  the  remains  of  the  creature  to  which  the  Globigerina 
shell,  or  rather  skeleton,  owes  its  existence — and  which  is  an 


206  ACHIEVEMENTS  IN  SCIENCE 

animal  of  the  simplest  imaginable  description.  It  is,  in  fact,  a 
mere  particle  of  living  jelly,  without  defined  parts  of  any  kind 
— without  a  mouth,  nerves,  muscles,  or  distinct  organs,  and 
only  manifesting  its  vitality  to  ordinary  observation  by  thrust- 
ing out  and  retracting  from  all  parts  of  its  surface  long  fila- 
mentous processes,  which  serve  for  arms  and  legs.  Yet  this 
amorphous  particle,  devoid  of  everything  which,  in  the  higher 
animals,  we  call  organs,  is  capable  of  feeding,  growing,  and 
multiplying ;  of  separating  from  the  ocean  the  small  proportion 
of  carbonate  of  lime  which  is  dissolved  in  sea-water;  and  of 
building  up  that  substance  into  a  skeleton  for  itself  according 
to  a  pattern  which  can  be  imitated  by  no  other  known 
agency. 

The  notion  that  animals  can  live  and  flourish  in  the  sea,  at 
the  vast  depths  from  which  apparently  living  Globigerinae  have 
been  brought  up,  does  not  agree  very  well  with  our  usual  con- 
ceptions respecting  the  conditions  of  animal  life;  and  it  is  not 
so  absolutely  impossible  as  it  might  at  first  appear  to  be,  that 
the  Globigerinae  of  the  Atlantic  sea-bottom  do  not  live  and  die 
where  they  are  found. 

As  I  have  mentioned,  the  soundings  from  the  great  Atlantic 
plain  are  almost  entirely  made  up  of  Globigerinae,  with  the 
granules  which  have  been  mentioned,  and  some  few  other  cal- 
careous shells ;  but  a  small  percentage  of  the  chalky  mud— 
perhaps  at  most  some  five  per  cent,  of  it — is  of  a  different 
nature,  and  consists  of  shells  and  skeletons  composed  of  silex, 
or  pure  flint.  These  siliceous  bodies  belong  partly  to  the  lowly 
vegetable  organisms  which  are  called  Diatomaceae,  and  partly  to 
the  minute  and  extremely  simple  animals  termed  Radiolaria. 
It  is  quite  certain  that  these  creatures  do  not  live  at  the  bottom 
of  the  ocean,  but  at  its  surface — where  they  may  be  obtained 
in  prodigious  numbers  by  the  use  of  a  properly  constructed 
net.  Hence  it  follows  that  these  siliceous  organisms,  though 
they  are  not  heavier  than  the  lightest  dust,  must  have  fallen, 
in  some  cases,  through  1 5,000  feet  of  water,  before  they  reached 
their  final  resting-place  on  the  ocean  floor.  And,  considering 
how  large  a  surface  these  bodies  expose  in  proportion  to  their 
weight,  it  is  probable  that  they  occupy  a  great  length  of  time 


GEOLOGY  207 

in  making  their  burial  journey  from  the  surface  of  the  Atlantic 
to  the  bottom. 

But  if  the  Radiolaria  and  Diatoms  are  thus  rained  upon 
the  bottom  of  the  sea,  from  the  superficial  layer  of  its  waters 
in  which  they  pass  their  lives,  it  is  obviously  possible  that  the 
Globigerinae  may  be  similarly  derived ;  and  if  they  were  so,  it 
would  be  much  more  easy  to  understand  how  they  obtain  their 
supply  of  food  than  it  is  at  present.  Nevertheless,  the  positive 
and  negative  evidence  all  points  the  other  way.  The  skeletons 
of  the  full-grown,  deep-sea  Globigerinae  are  so  remarkably  solid 
and  heavy  in  proportion  to  their  surface  as  to  seem  little  fitted 
for  floating ;  and,  as  a  matter  of  fact,  they  are  not  to  be  found 
along  with  the  Diatoms  and  Radiolaria,  in  the  uppermost 
stratum  of  the  open  ocean. 

It  has  been  observed,  again,  that  the  abundance  of  Globige- 
rinae, in  proportion  to  other  organisms  of  like  kind,  increases 
with  the  depth  of  the  sea ;  and  that  deep-water  Globigerinae  are 
larger  than  those  which  live  in  the  shallower  parts  of  the  sea ; 
and  such  facts  negative  the  supposition  that  these  organisms 
have  been  swept  by  currents  from  the  shallows  into  the  deeps 
of  the  Atlantic. 

It  therefore  seems  to  be  hardly  doubtful  that  these  wonder- 
il  creatures  live  and  die  at  the  depths  in  which  they  are  found. 

However,  the  important  points  for  us  are,  that  the  living 
Globigerinae  are  exclusively  marine  animals,  the  skeletons  of 
which  abound  at  the  bottom  of  deep  seas ;  and  that  there  is  not 
a  shadow  of  reason  for  believing  that  the  habits  of  the  Globige- 
rinae of  the  chalk  differed  from  those  of  the  existing  species. 
But  if  this  be  true,  there  is  no  escaping  the  conclusion  that  the 
chalk  itself  is  the  dried  mud  of  an  ancient  deep  sea. 

In  working  over  the  soundings  collected  by  Captain  Day- 
man, I  was  surprised  to  find  that  many  of  what  I  have  called 
the  "  granules  "  of  that  mud  were  not,  as  one  might  have  been 
tempted  to  think  at  first,  the  mere  powder  and  waste  of  Globi- 
gerinae, but  that  they  had  a  definite  form  and  size.  I  termed 
these  bodies  "  coccoliths"  and  doubted  their  organic  nature. 
Dr.  Wallich  verified  my  observation,  and  added  the  interest- 
ing discovery  that,  not  infrequently,  bodies  similar  to  these 


208  ACHIEVEMENTS  IN  SCIENCE 

"  coccoliths  "  were  aggregated  together  into  spheroids,  which 
he  termed  "  coccospheres  "  So  far  as  we  knew,  these  bodies, 
the  nature  of  which  is  extremely  puzzling  and  problematical, 
were  peculiar  to  the  Atlantic  soundings. 

But,  a  few  years  ago,  Mr.  Sorby,  in  making  a  careful  exam- 
ination of  the  chalk  by  means  of  thin  sections  and  otherwise, 
observed,  as  Ehrenberg  had  done  before  him,  that  much  of  its 
granular  basis  possesses  a  definite  form.  Comparing  these 
formed  particles  with  those  in  the  Atlantic  soundings,  he  found 
the  two  to  be  identical ;  and  thus  proved  that  the  chalk,  like 
the  soundings,  contains  these  mysterious  coccoliths  and  cocco- 
spheres.  Here  was  a  further  and  a  most  interesting  confirma- 
tion, from  internal  evidence,  of  the  essential  identity  of  the 
chalk  with  modern  deep-sea  mud.  Globigerinae,  coccoliths, 
and  coccospheres  are  found  as  the  chief  constituents  of  both, 
and  testify  to  the  general  similarity  of  the  conditions  under 
which  both  have  been  formed. 

The  evidence  furnished  by  the  hewing,  facing,  and  superpo- 
sition of  the  stones  of  the  Pyramids,  that  these  structures  were 
built  by  men,  has  no  greater  weight  than  the  evidence  that  the 
chalk  was  built  by  Globigerinae;  and  the  belief  that  those 
ancient  pyramid-builders  were  terrestrial  and  air-breathing 
creatures  like  ourselves,  is  not  better  based  than  the  conviction 
that  the  chalk-makers  lived  in  the  sea. 

But  as  our  belief  in  the  building  of  the  Pyramids  by  men  is 
not  only  grounded  on  the  internal  evidence  afforded  by  these 
structures,  but  gathers  strength  from  multitudinous  collateral 
proofs,  and  is  clinched  by  the  total  absence  of  any  reason  for 
a  contrary  belief ;  so  the  evidence  drawn  from  the  Globigerinae 
that  the  chalk  is  an  ancient  sea-bottom,  is  fortified  by  innumera- 
ble independent  lines  of  evidence ;  and  our  belief  in  the  truth 
of  the  conclusion  to  which  all  positive  testimony  tends,  re- 
ceives the  like  negative  justification  from  the  fact  that  no  other 
hypothesis  has  a  shadow  of  foundation. 

It  may  be  worth  while  briefly  to  consider  a  few  of  these  col- 
lateral proofs  that  the  chalk  was  deposited  at  the  bottom  of  the 
sea. 

The  great  mass  of  the  chalk  is  composed,  as  we  have  seen, 


GEOLOGY  209 

of  the  skeletons  of  Globigerinae,  and  other  simple  organisms, 
imoedded  in  granular  matter.  Here  and  there,  however,  this 
hardened  mud  of  the  ancient  sea  reveals  the  remains  of  higher 
animals  which  have  lived  and  died,  and  left  their  hard  parts  in 
the  mud,  just  as  the  oysters  die  and  leave  their  shells  behind 
them  in  the  mud  of  the  present  seas. 

There  are,  at  the  present  day,  certain  groups  of  animals 
which  are  never  found  in  fresh  waters,  being  unable  to  live 
anywhere  but  in  the  sea.  Such  are  the  corals ;  those  corallines 
which  are  called  Polyzoa;  those  creatures  which  fabricate  the 
lamp-shells,  and  are  called  Brachiopoda;  the  pearly  Nautilus, 
and  all  animals  allied  to  it;  and  all  the  forms  of  sea-urchins 
and  star-fishes. 

Not  only  are  all  these  creatures  confined  to  salt  water  at 
the  present  day,  but,  so  far  as  our  records  of  the  past  go,  the 
conditions  of  their  existence  have  been  the  same :  hence,  their 
occurrence  in  any  deposit  is  as  strong  evidence  as  can  be  ob- 
tained, that  that  deposit  was  formed  in  the  sea.  Now,  the  re- 
mains of  animals  of  all  the  kinds  which  have  been  enumerated 
occur  in  the  chalk,  in  greater  or  less  abundance ;  while  not  one 
of  those  forms  of  shell-fish  which  are  characteristic  of  fresh 
water  has  yet  been  observed  in  it. 

When  we  consider  that  the  remains  of  more  than  three 
thousand  distinct  species  of  aquatic  animals  have  been  discov- 
ered among  the  fossils  of  the  chalk,  that  the  great  majority  of 
them  are  of  such  forms  as  are  now  met  with  only  in  the  sea, 
and  that  there  is  no  reason  to  believe  that  any  one  of  them  in- 
habited fresh  water — the  collateral  evidence  that  the  chalk  rep- 
resents an  ancient  sea-bottom  acquires  as  great  force  as  the 
proof  derived  from  the  nature  of  the  chalk  itself.  I  think  you 
will  now  allow  that  I  did  not  overstate  my  case  when  I  asserted 
that  we  have  as  strong  grounds  for  believing  that  all  the  vast 
area  of  dry  land  at  present  occupied  by  the  chalk  was  once  at 
the  bottom  of  the  sea,  as  we  have  for  any  matter  of  history 
whatever;  while  there  is  no  justification  for  any  other 
belief. 

No  less  certain  is  it  that  the  time  during  which  the  coun- 
tries we  now  call  southeast  England,  France,  Germany,  Poland, 


210  ACHIEVEMENTS  IN  SCIENCE 

Russia,  Egypt,  Arabia,  Syria,  were  more  or  less  completely 
covered  by  a  deep  sea,  was  of  considerable  duration. 

We  have  already  seen  that  the  chalk  is,  in  places,  more 
than  a  thousand  feet  thick.  I  think  you  will  agree  with  me 
that  it  must  have  taken  some  time  for  the  skeletons  of  the  ani- 
malcules of  a  hundredth  of  an  inch  in  diameter  to  heap  up  such 
a  mass  as  that.  I  have  said  that  throughout  the  thickness  of 
the  chalk  the  remains  of  other  animals  are  scattered.  These 
remains  are  often  in  the  most  exquisite  state  of  preservation. 
The  valves  of  the  shell-fishes  are  commonly  adherent ;  the  long 
spines  of  some  of  the  sea-urchins,  which  would  be  detached  by 
the  smallest  jar,  often  remain  in  their  places.  In  a  word,  it  is 
certain  that  these  animals  have  lived  and  died  when  the  place 
which  they  now  occupy  was  the  surface  of  as  much  of  the  chalk 
as  had  then  been  deposited ;  and  that  each  has  been  covered  up 
by  the  layer  of  Globigerina  mud,  upon  which  the  creatures  im- 
bedded a  little  higher  up  have,  in  like  manner,  lived  and  died. 
But  some  of  these  remains  prove  the  existence  of  reptiles  of 
vast  size  in  the  chalk  sea.  These  lived  their  time,  and  had 
their  ancestors  and  descendants,  which  assuredly  implies  time, 
reptiles  being  of  slow  growth.  There  is  more  curious  evidence, 
again,  that  the  process  of  covering  up,  or,  in  other  words,  the 
deposit  of  Globigerina  skeletons,  did  not  go  on  very  fast.  It  is 
demonstrable  that  an  animal  of  the  cretaceous  sea  might  die, 
that  its  skeleton  might  lie  uncovered  upon  the  sea-bottom  long 
enough  to  lose  all  its  outward  coverings  and  appendages  by 
putrefaction ;  and  that,  after  this  had  happened,  another  animal 
might  attach  itself  to  the  dead  and  naked  skeleton,  might  grow 
to  maturity,  and  might  itself  die  before  the  calcareous  mud  had 
buried  the  whole. 

Cases  of  this  kind  are  admirably  described  by  Sir  Charles 
Lyell.  He  speaks  of  the  frequency  with  which  geologists  find 
in  the  chalk  a  fossilized  sea-urchin  to  which  is  attached  the 
lower  valve  of  a  Crania.  This  is  a  kind  of  shell-fish,  with  a 
shell  composed  of  two  pieces,  of  which,  as  in  the  oyster,  one  is 
fixed  and  the  other  free. 

"  The  upper  valve  is  almost  invariably  wanting,  though  occa- 
sionally found  in  a  perfect  state  of  preservation  in  the  white 


GEOLOGY  211 

chalk  at  some  distance.  In  this  case,  we  see  clearly  that  the 
sea-urchin  first  lived  from  youth  to  age,  then  died  and  lost  its 
spines,  which  were  carried  away.  Then  the  young  Crania 
adhered  to  the  bared  shell,  grew  and  perished  in  its  turn ;  after 
which,  the  upper  valve  was  separated  from  the  lower,  before 
the  Echinus  became  enveloped  in  chalky  mud." 

A  specimen  in  the  Museum  of  Practical  Geology,  in  Lon- 
don, still  further  prolongs  the  period  which  must  have  elapsed 
between  the  death  of  the  sea-urchin  and  its  burial  by  the  Globig- 
erinae.  For  the  outward  face  of  the  valve  of  a  Crania,  which  is 
attached  to  a  sea-urchin  (Micraster),  is  itself  overrun  by  an  in- 
crusting  coralline,  which  spreads  thence  over  more  or  less  of 
the  surface  of  the  sea-urchin.  It  follows  that,  after  the  upper 
valve  of  the  Crania  fell  off,  the  surface  of  the  attached  valve 
must  have  remained  exposed  long  enough  to  allow  of  the 
growth  of  the  whole  coralline,  since  corallines  do  not  live  im- 
bedded in  the  mud. 

The  progress  of  knowledge  may,  one  day,  enable  us  to  de- 
duce from  such  facts  as  these  the  maximum  rate  at  which  the 

ilk  can  have  accumulated,  and  thus  to  arrive  at  the  minimum 
luration  of  the  chalk  period.  Suppose  that  the  valve  of  the 
Crania  upon  which  a  coralline  has  fixed  itself  in  the  way  just 
lescribed  is  so  attached  to  the  sea-urchin  that  no  part  of  it  is 
lore  than  an  inch  above  the  face  upon  which  the  sea-urchin 
rests.  Then,  as  the  coralline  could  not  have  fixed  itself  if  the 
Crania  had  been  covered  up  with  chalk-mud,  and  could  not 
ive  lived  had  itself  been  so  covered,  it  follows  that  an  inch  of 
chalk  mud  could  not  have  accumulated  within  the  time  between 
the  death  and  decay  of  the  soft  parts  of  the  sea-urchin  and  the 
rowth  of  the  coralline  to  the  full  size  which  it  has  attained. 
If  the  decay  of  the  soft  parts  of  the  sea-urchin ;  the  attachment, 
growth  to  maturity,  and  decay  of  the  Crania;  and  the  subse- 
quent attachment  and  growth  of  the  coralline,  took  a  year 
(which  is  a  low  estimate  enough),  the  accumulation  of  the  inch 
of  chalk  must  have  taken  more  than  a  year :  and  the  deposit  of 
thousand  feet  of  chalk  must,  consequently,  have  taken  more 
:han  twelve  thousand  years. 

The  foundation  of  all  this  calculation  is,  of  course,  a  knowl- 


212  ACHIEVEMENTS  IN  SCIENCE 

edge  of  the  length  of  time  the  Crania  and  the  coralline  needed 
to  attain  their  full  size ;  and,  on  this  head,  precise  knowledge  is 
at  present  wanting.  But  there  are  circumstances  which  tend 
to  show  that  nothing  like  an  inch  of  chalk  has  accumulated 
during  the  life  of  a  Crania ;  and,  on  any  probable  estimate  of 
the  length  of  that  life,  the  chalk  period  must  have  had  a  much 
longer  duration  than  that  thus  roughly  assigned  to  it. 

Thus,  not  only  is  it  certain  that  the  chalk  is  the  mud  of  an 
ancient  sea-bottom ;  but  it  is  no  less  certain  that  the  chalk  sea 
existed  during  an  extremely  long  period,  though  we  may  not 
be  prepared  to  give  a  precise  estimate  of  the  length  of  that 
period  in  years.  The  relative  duration  is  clear,  though  the 
absolute  duration  may  not  be  definable.  The  attempt  to  affix 
any  precise  date  to  the  period  at  which  the  chalk  sea  began  or 
ended  its  existence,  is  baffled  by  difficulties  of  the  same  kind. 
But  the  relative  age  of  the  Cretaceous  epoch  may  be  determined 
with  as  great  ease  and  certainty  as  the  long  duration  of  that 
epoch. 

You  will  have  heard  of  the  interesting  discoveries  recently 
made,  in  various  parts  of  Western  Europe,  of  flint  implements, 
obviously  worked  into  shape  by  human  hands,  under  circum- 
stances which  show  conclusively  that  man  is  a  very  ancient 
denizen  of  these  regions. 

It  has  been  proved  that  the  old  populations  of  Europe, 
whose  existence  has  been  revealed  to  us  in  this  way,  consisted 
of  savages,  such  as  the  Esquimaux  are  now ;  that,  in  the  coun- 
try which  is  now  France,  they  hunted  the  reindeer,  and  were 
familiar  with  the  ways  of  the  mammoth  and  the  bison.  The 
physical  geography  of  France  was  in  those  days  different  from 
what  it  is  now — the  river  Somme,  for  instance,  having  cut  its 
bed  a  hundred  feet  deeper  between  that  time  and  this ;  and  it 
is  probable  that  the  climate  was  more  like  that  of  Canada  or 
Siberia  than  that  of  Western  Europe. 

The  existence  of  these  people  is  forgotten  even  in  the  tradi- 
tions of  the  oldest  historical  nations.  The  name  and  fame  of 
them  had  utterly  vanished  until  a  few  years  back;  and  the 
amount  of  physical  change  which  has  been  effected  since  their 
day  renders  it  more  than  probable  that,  venerable  as  are  some 


GEOLOGY  213 

of  the  historical  nations,  the  workers  of  the  chipped  flints  of 
Hoxne  or  of  Amiens  are  to  them,  as  they  are  to  us,  in  point  of 
antiquity. 

But,  if  we  assign  to  these  hoar  relics  of  long-vanished  gener- 
ations of  men  the  greatest  age  that  can  possibly  be  claimed  for 
them,  they  are  not  older  than  the  drift,  or  bowlder  clay,  which, 
in  comparison  with  the  chalk,  is  but  a  very  juvenile  deposit. 
You  need  go  no  further  than  your  own  seaboard  for  evidence 
of  this  fact.  At  one  of  the  most  charming  spots  on  the  coast 
of  Norfolk,  Cromer,  you  will  see  the  bowlder  clay  forming  a 
vast  mass,  which  lies  upon  the  chalk,  and  must  consequently 
have  come  into  existence  after  it.  Huge  bowlders  of  chalk 
are,  in  fact,  included  in  the  clay,  and  have  evidently  been 
brought  to  the  position  they  now  occupy  by  the  same  agency 
as  that  which  has  planted  blocks  of  syenite  from  Norway  side 
by  side  with  them. 

The  chalk,  then,  is  certainly  older  than  the  bowlder  clay. 
If  you  ask  how  much,  I  will  again  take  you  no  further  than  the 
same  spot  upon  your  own  coasts  for  evidence.  I  have  spoken 
of  the  bowlder  clay  and  drift  as  resting  upon  the  chalk.  That 
is  not  strictly  true.  Interposed  between  the  chalk  and  the 
drift  is  a  comparatively  insignificant  layer,  containing  vegetable 
matter.  But  that  layer  tells  a  wonderful  history.  It  is  full  of 
stumps  of  trees  standing  as  they  grew.  Fir-trees  are  there  with 
their  cones,  and  hazel-bushes  with  their  nuts ;  there  stand  the 
stools  of  oak  and  yew  trees,  beeches  and  alders.  Hence  this 
stratum  is  appropriately  called  the  "  forest-bed." 

It  is  obvious  that  the  chalk  must  have  been  upheaved  and 
converted  into  dry  land  before  the  timber  trees  could  grow 
upon  it.  As  the  bolls  of  some  of  these  trees  are  from  two  to 
three  feet  in  diameter,  it  is  no  less  clear  that  the  dry  land  thus 
formed  remained  in  the  same  condition  for  long  ages.  And 
not  only  do  the  remains  of  stately  oaks  and  well-grown  firs 
testify  to  the  duration  of  this  condition  of  things,  but  additional 
evidence  to  the  same  effect  is  afforded  by  the  abundant  remains 
of  elephants,  rhinoceroses,  hippopotamuses,  and  other  great 
wild  beasts,  which  it  has  yielded  to  the  zealous  search  of  such 
men  as  the  Rev.  Mr.  Gunn. 


214  ACHIEVEMENTS  IN  SCIENCE 

When  you  look  at  such  a  collection  as  he  has  formed,  and 
bethink  you  that  these  elephantine  bones  did  veritably  carry 
their  owners  about,  and  these  great  grinders  crunch,  in  the 
dark  woods  of  which  the  forest-bed  is  now  the  only  trace,  it  is 
impossible  not  to  feel  that  they  are  as  good  evidence  of  the 
lapse  of  time  as  the  annual  rings  of  the  tree-stumps. 

Thus  there  is  a  writing  upon  the  wall  of  cliffs  at  Cromer, 
and  whoso  runs  may  read  it.  It  tells  us,  with  an  authority 
which  cannot  be  impeached,  that  the  ancient  sea-bed  of  the 
chalk  sea  was  raised  up,  and  remained  dry  land,  until  it  was 
covered  with  forest,  stocked  with  the  great  game  whose  spoils 
have  rejoiced  your  geologists.  How  long  it  remained  in  that 
condition  cannot  be  said ;  but  "  the  whirligig  of  time  brought 
its  revenges  "  in  those  days  as  in  these.  That  dry  land,  with 
the  bones  and  teeth  of  generations  of  long-lived  elephants,  hid- 
den away  among  the  gnarled  roots  and  dry  leaves  of  its  ancient 
trees,  sank  gradually  to  the  bottom  of  the  icy  sea,  which  cov- 
ered it  with  huge  masses  of  drift  and  bowlder  clay.  Sea-beasts, 
such  as  the  walrus,  now  restricted  to  the  extreme  north,  pad- 
dled about  where  birds  had  twittered  among  the  topmost  twigs 
of  the  fir-trees.  How  long  this  state  of  things  endured  we 
know  not,  but  at  last  it  came  to  an  end.  The  upheaved 
glacial  mud  hardened  into  the  soil  of  modern  Norfolk.  Forests 
grew  once  more,  the  wolf  and  the  beaver  replaced  the  reindeer 
and  the  elephant ;  and  at  length  what  we  call  the  history  of 
England  dawned. 

Thus  you  have,  within  the  limits  of  your  own  county,  proof 
that  the  chalk  can  justly  claim  a  very  much  greater  antiquity 
than  even  the  oldest  physical  traces  of  mankind.  But  we  may 
go  further  and  demonstrate,  by  evidence  of  the  same  authority 
as  that  which  testifies  to  the  existence  of  the  father  of  men, 
that  the  chalk  is  vastly  older  than  Adam  himself. 

The  Book  of  Genesis  informs  us  that  Ada'm,  immediately 
upon  his  creation,  and  before  the  appearance  of  Eve,  was  placed 
in  the  garden  of  Eden.  The  problem  of  the  geographical  posi- 
tion of  Eden  has  greatly  vexed  the  spirits  of  the  learned  in  such 
matters,  but  there  is  one  point  respecting  which,  so  far  as  I 
know,  no  commentator  has  ever  raised  a  doubt.  This  is,  that 


GEOLOGY  215 

of  the  four  rivers  which  are  said  to  run  out  of  it,  Euphrates 
and  Hiddekel  are  identical  with  the  rivers  now  known  by  the 
names  of  Euphrates  and  Tigris. 

But  the  whole  country  in  which  these  mighty  rivers  take 
their  origin,  and  through  which  they  run,  is  composed  of  rocks 
which  are  either  of  the  same  age  as  the  chalk,  or  of  later  date. 
So  that  the  chalk  must  not  only  have  been  formed,  but,  after 
its  formation,  the  time  required  for  the  deposit  of  these  later 
rocks,  and  for  their  upheaval  into  dry  land,  must  have  elapsed, 
before  the  smallest  brook  which  feeds  the  swift  stream  of  "  the 
great  river,  the  river  of  Babylon,"  began  to  flow. 

Thus,  evidence  which  cannot  be  rebutted,  and  which  need 
not  be  strengthened,  though  if  time  permitted  I  might  indefi- 
nitely increase  its  quantity,  compels  you  to  believe  that  the 
earth,  from  the  time  of  the  chalk  to  the  present  day,  has  been 
the  theater  of  a  series  of  changes  as  vast  in  their  amount  as 
they  were  slow  in  their  progress.  The  area  on  which  we  stand 
has  been  first  sea  and  then  land,  for  at  least  four  alternations ; 
and  has  remained  in  each  of  these  conditions  for  a  period  of 
great  length. 

Nor  have  these  wonderful  metamorphoses  of  sea  into  land, 
d  of  land  into  sea,  been  confined  to  one  corner  of  England, 
uring  the  Chalk  period,  or  "  Cretaceous  epoch,"  not  one  of  the 
present  great  physical  features  of  the  globe  was  in  existence. 
Our  great  mountain  ranges  Pyrenees,  Alps,  Himalayas,  Andes, 
have  all  been  upheaved  since  the  chalk  was  deposited,  and  the 
cretaceous  sea  flowed  over  the  sites  of  Sinai  and  Ararat. 

All  this  is  certain,  because  rocks  of  cretaceous  or  still  later 
date  have  shared  in  the  elevatory  movements  which  gave  rise 
to  these  mountain  chains ;  and  may  be  found  perched  up,  in 
some  cases,  many  thousand  feet  high  upon  their  flanks.  And 
evidence  of  equal  cogency  demonstrates  that,  though  in  Norfolk 
the  forest-bed  rests  directly  upon  the  chalk,  yet  it  does  so,  not 
because  the  period  at  which  the  forest  grew  immediately  fol- 
lowed that  at  which  the  chalk  was  formed,  but  because  an  im- 
mense lapse  of  time,  represented  elsewhere  by  thousands  of 
feet  of  rock,  is  not  indicated  at  Cromer. 


216  ACHIEVEMENTS  IN  SCIENCE 

I  must  ask  you  to  believe  that  there  is  no  less  conclusive 
proof  that  a  still  more  prolonged  succession  of  similar  changes 
occurred  before  the  chalk  was  deposited.  Nor  have  we  any 
reason  to  think  that  the  first  term  in  the  series  of  these  changes 
is  known.  The  oldest  sea-beds  preserved  to  us  are  sands,  and 
mud,  and  pebbles,  the  wear  and  tear  of  rocks  which  were  formed 
in  still  older  oceans. 

But,  great  as  is  the  magnitude  of  these  physical  changes  of 
the  world,  they  have  been  accompanied  by  a  no  less  striking 
series  of  modifications  in  its  living  inhabitants. 

All  the  great  classes  of  animals,  beasts  of  the  field,  fowls  of 
the  air,  creeping  things,  and  things  which  dwell  in  the  waters, 
flourished  upon  the  globe  long  ages  before  the  chalk  was  de- 
posited. Very  few,  however,  if  any,  of  these  ancient  forms  of 
animal  life  were  identical  with  those  which  now  live.  Certainly 
not  one  of  the  higher  animals  was  of  the  same  species  as  any 
of  those  now  in  existence.  The  beasts  of  the  field,  in  the  days 
before  the  chalk,  were  not  our  beasts  of  the  field,  nor  the  fowls 
of  the  air  such  as  those  which  the  eye  of  man  has  seen  flying, 
unless  his  antiquity  dates  infinitely  further  back  than  we  at 
present  surmise.  If  we  could  be  carried  back  into  those  times, 
we  should  be  as  one  suddenly  set  down  in  Australia  before  it 
was  colonized.  We  should  see  mammals,  birds,  reptiles,  fishes, 
insects,  snails,  and  the  like,  clearly  recognizable  as  such, 
and  yet  not  one  of  them  would  be  just  the  same  as  those 
with  which  we  are  familiar,  and  many  would  be  extremely 
different. 

From  that  time  to  the  present,  the  population  of  the  world 
has  undergone  slow  and  gradual,  but  incessant,  changes. 
There  has  been  no  grand  catastrophe — no  destroyer  has  swept 
away  the  forms  of  life  of  one  period,  and  replaced  them  by  a 
totally  new  creation ;  but  one  species  has  vanished  and  another 
has  taken  its  place ;  creatures  of  one  type  of  structure  have 
diminished,  those  of  another  have  increased,  as  time  has  passed 
on.  And  thus,  while  the  differences  between  the  living  crea- 
tures of  the  time  before  the  chalk  and  those  of  the  present  day 
appear  startling,  if  placed  side  by  side,  we  are  led  from  one  to 
the  other  by  the  most  gradual  progress,  if  we  follow  the  course 


GEOLOGY  217 

of  Nature  through  the  whole  series  of  those  relics  of  her  opera- 
tions which  she  has  left  behind. 

And  it  is  by  the  population  of  the  chalk  sea  that  the  ancient 
and  the  modern  inhabitants  of  the  world  are  most  completely 
connected.  The  groups  which  are  dying  out  flourish,  side  by 
side,  with  the  groups  which  are  now  the  dominant  forms  of  life. 

Thus  the  chalk  contains  remains  of  those  flying  and  swim- 
ming reptiles,  the  pterodactyl,  the  ichthyosaurus,  and  the  plesio- 
saurus,  which  are  found  in  no  later  deposits,  but  abounded  in 
preceding  ages.  The  chambered  shells  called  ammonites  and 
belemnites,  which  are  so  characteristic  of  the  period  preceding 
the  cretaceous,  in  like  manner  die  with  it. 

But,  among  these  fading  reminders  of  a  previous  state  of 
things,  are  some  very  modern  forms  of  life,  looking  like  Yankee 
peddlers  among  a  tribe  of  red  Indians.  Crocodiles  of  modern 
type  appear;  bony  fishes,  many  of  them  very  similar  to  exist- 
ing species,  almost  supplant  the  forms  of  fish  which  predomi- 
nate in  more  ancient  seas;  and  many  kinds  of  living  shell-fish 
first  become  known  to  us  in  the  chalk.  The  vegetation  acquires 
a  modern  aspect.  A  few  living  animals  are  not  even  distin- 
guishable as  species  from  those  which  existed  at  that  remote 
epoch.  The  Globigerina  of  the  present  day,  for  example,  is 
not  different  specifically  from  that  of  the  chalk ;  and  the  same 
may  be  said  of  many  other  Foraminifera.  I  think  it  probable 
that  critical  and  unprejudiced  examination  will  show  that  more 
than  one  species  of  much  higher  animals  have  had  a  similar 
longevity ;  but  the  only  example  which  I  can  at  present  give 
confidently  is  the  snake' s-head  lamp-shell  (  Terebratulina  caput 
serpentis),  which  lives  in  our  English  seas  and  abounded  (as 
Terebratulina  striata  of  authors)  in  the  chalk. 

The  longest  line  of  human  ancestry  must  hide  its  diminished 
head  before  the  pedigree  of  this  insignificant  shell-fish.  We 
Englishmen  are  proud  to  have  an  ancestor  who  was  present  at 
the  battle  of  Hastings.  The  ancestors  of  Terebratulina  caput 
serpentis  may  have  been  present  at  a  battle  of  Ichthyosauria  in 
that  part  of  the  sea  which,  when  the  chalk  was  forming,  flowed 
over  the  site  of  Hastings.  While  all  around  has  changed,  this 
Terebratulina  has  peacefully  propagated  its  species  from  gener- 


218  ACHIEVEMENTS  IN  SCIENCE 

ation  to  generation,  and  stands  to  this  day  as  a  living  testimony 
to  the  continuity  of  the  present  with  the  past  history  of  the 
globe. 

Up  to  this  moment  I  have  stated,  so  far  as  I  know,  nothing 
but  well-authenticated  facts,  and  the  immediate  conclusions 
which  they  force  upon  the  mind. 

But  the  mind  is  so  constituted  that  it  does  not  willingly  rest 
in  facts  and  immediate  causes,  but  seeks  always  after  a  knowl- 
edge of  the  remoter  links  in  the  chain  of  causation. 

Taking  the  many  changes  of  any  given  spot  of  the  earth's 
surface,  from  sea  to  land,  and  from  land  to  sea,  as  an  estab- 
lished fact,  we  cannot  refrain  from  asking  ourselves  how  these 
changes  have  occurred.  And  when  we  have  explained  them— 
as  they  must  be  explained — by  the  alternate  slow  movements 
of  elevation  and  depression  which  have  affected  the  crusts  of 
the  earth,  we  go  still  further  back,  and  ask,  Why  these  move- 
ments ? 

I  am  not  certain  that  any  one  can  give  you  a  satisfactory 
answer  to  that  question.  Assuredly  I  cannot.  All  that  can 
be  said  for  certain  is,  that  such  movements  are  part  of  the  ordi- 
nary course  of  nature,  inasmuch  as  they  are  going  on  at  the 
present  time.  Direct  proof  may  be  given,  that  some  parts  of 
the  land  of  the  northern  hemisphere  are  at  this  moment  insen- 
sibly rising  and  others  insensibly  sinking ;  and  there  is  indirect 
but  perfectly  satisfactory  proof,  that  an  enormous  area  now 
covered  by  the  Pacific  has  been  deepened  thousands  of  feet 
since  the  present  inhabitants  of  that  sea  came  into  existence. 

Thus  there  is  not  a  shadow  of  a  reason  for  believing  that 
the  physical  changes  of  the  globe,  in  past  times,  have  been 
effected  by  other  than  natural  causes. 

Is  there  any  more  reason  for  believing  that  the  concomitant 
modifications  in  the  forms  of  the  living  inhabitants  of  the  globe 
have  been  brought  about  in  any  other  way  ? 

Before  attempting  to  answer  this  question,  let  us  try  to 
form  a  distinct  mental  picture  of  what  has  happened  in  some 
special  case. 

The  crocodiles  are  animals  which,  as  a  group,  have  a  very 


GEOLOGY  219 

vast  antiquity.  They  abounded  ages  before  the  chalk  was  de- 
posited ;  they  throng  the  rivers  in  warm  climates  at  the  present 
day.  There  is  a  difference  in  the  form  of  the  joints  of  the  back- 
bone, and  in  some  minor  particulars,  between  the  crocodiles  of 
the  present  epoch  and  those  which  lived  before  the  chalk ;  but, 
in  the  Cretaceous  epoch,  as  I  have  already  mentioned,  the  croco- 
diles had  assumed  the  modern  type  of  structure.  Notwith- 
standing this,  the  crocodiles  of  the  chalk  are  not  identically  the 
same  as  those  which  lived  in  the  times  called  "older  tertiary," 
which  succeeded  the  Cretaceous  epoch ;  and  the  crocodiles  of 
the  older  tertiaries  are  not  identical  with  those  of  the  newer 
tertiaries,  nor  are  these  identical  with  existing  forms.  I  leave 
open  the  question  whether  particular  species  may  have  lived  on 
from  epoch  to  epoch.  But  each  epoch  has  had  its  peculiar 
crocodiles;  though  all,  since  the  chalk,  have  belonged  to  the 
modern  type,  and  differ  simply  in  their  proportions  and  in  such 
structural  particulars  as  are  discernible  only  to  trained  eyes. 

How  is  the  existence  of  this  long  succession  of  different 
species  of  crocodiles  to  be  accounted  for  ? 

Only  two  suppositions  seem  to  be  open  to  us — either  each 
species  of  crocodile  has  been  specially  created,  or  it  has  arisen 
out  of  some  preexisting  form  by  the  operation  of  natural 
causes. 

Choose  your  hypothesis ;  I  have  chosen  mine.  I  can  find 
no  warranty  for  believing  in  the  distinct  creation  of  a  score  of 
successive  species  of  crocodiles  in  the  course  of  countless  ages 
of  time.  Science  gives  no  countenance  to  such  a  wild  fancy ; 
nor  can  even  the  perverse  ingenuity  of  a  commentator  pretend 
to  discover  this  sense,  in  the  simple  words  in  which  the  writer 
of  Genesis  records  the  proceeding  of  the  fifth  and  sixth  days  of 
the  Creation. 

On  the  other  hand,  I  see  no  good  reason  for  doubting  the 
necessary  alternative,  that  all  these  varied  species  have  been 
evolved  from  preexisting  crocodilian  forms  by  the  operation  of 
causes  as  completely  a  part  of  the  common  order  of  nature  as 
those  which  have  effected  the  changes  of  the  inorganic  world. 

Few  will  venture  to  affirm  that  the  reasoning  which  applies 

crocodiles  loses  its  force  among  other  animals  or  among 


220  ACHIEVEMENTS  IN  SCIENCE 

plants.  If  one  series  rof  species  has  come  into  existence  by  the 
operation  of  natural  causes,  it  seems  folly  to  deny  that  all  may 
have  arisen  in  the  same  way. 

A  small  beginning  has  led  us  to  a  great  ending.  If  I  were 
to  put  the  bit  of  chalk  with  which  we  started  into  the  hot  but 
obscure  flame  of  burning  hydrogen,  it  would  presently  shine 
like  the  sun.  It  seems  to  me  that  this  physical  metamorphosis 
is  no  false  image  of  what  has  been  the  result  of  our  subjecting 
it  to  a  jet  of  fervent,  though  nowise  brilliant,  thought  to-night. 
It  has  become  luminous,  and  its  clear  rays,  penetrating  the 
abyss  of  the  remote  past,  have  brought  within  our  ken  some 
stages  of  the  evolution  of  the  earth.  And  in  the  shifting 
"  without  haste,  but  without  rest,"  of  the  land  and  sea,  as  in  the 
endless  variation  of  the  forms  assumed  by  living  beings,  we 
have  observed  nothing  but  the  natural  product  of  the  forces 
originally  possessed  by  the  substance  of  the  universe. 


GEOLOGY 
Volcanoes 

By  L.  AGASSIZ 

FIRST-BORN  among  the  continents,  though  so  much  later 
in  culture  and  civilization  than  some  of  more  recent  birth, 
America,  so  far  as  her  physical  history  is  concerned,  has  been 
falsely  denominated  the  New  World.  Hers  was  the  first  dry 
land  lifted  out  of  the  waters,  hers  the  first  shore  washed  by  the 
ocean  that  enveloped  all  the  earth  beside ;  and  while  Europe 
was  represented  only  by  islands  rising  here  and  there  above 
the  sea,  America  already  stretched  an  unbroken  line  of  land 
from  Nova  Scotia  to  the  Far  West. 

In  the  present  state  of  our  knowledge,  our  conclusions  re- 
specting the  beginning  of  the  earth's  history,  the  way  in  which 
it  took  form  and  shape  as  a  distinct,  separate  planet,  must,  of 
course,  be  very  vague  and  hypothetical.  Yet  the  progress  of 
science  is  so  rapidly  reconstructing  the  past  that  we  may  hope 
to  solve  even  this  problem ;  and  to  one  who  looks  upon  man's 
appearance  upon  the  earth  as  the  crowning  work  in  a  succession 
of  creative  acts,  all  of  which  have  had  relation  to  his  coming  in 
the  end,  it  will  not  seem  strange  that  he  should  at  last  be 
allowed  to  understand  a  history  which  was  but  the  introduction 
to  his  own  existence.  It  is  my  belief  that  not  only  the  future, 
but  the  past  also,  is  the  inheritance  of  man,  and  that  we  shall 
yet  conquer  our  lost  birthright. 

Even  now  our  knowledge  carries  us  far  enough  to  warrant 
the  assertion  that  there  was  a  time  when  our  earth  was  in  a 
state  of  igneous  fusion,  when  no  ocean  bathed  it  and  no  atmos- 
phere surrounded  it,  when  no  wind  blew  over  it  and  no  rain  fell 

221 


222  ACHIEVEMENTS  IN  SCIENCE 

upon  it,  but  an  intense  heat  held  all  its  materials  in  solution. 
In  those  days  the  rocks  which  are  now  the  very  bones  and 
sinews  of  our  mother  Earth — her  granites,  her  porphyries,  her 
basalts,  her  syenites — were  melted  into  a  liquid  mass.  As  I 
am  writing  for  the  unscientific  reader,  who  may  not  be  familiar 
with  the  facts  through  which  these  inferences  have  been 
reached,  I  will  answer  here  a  question  which,  were  we  talking 
together,  he  might  naturally  ask  in  a  somewhat  skeptical  tone. 
How  do  you  know  that  this  state  of  things  ever  existed,  and, 
supposing  that  the  solid  materials  of  which  our  earth  consists 
were  ever  in  a  liquid  condition,  what  right  have  you  to  infer 
that  this  condition  was  caused  by  the  action  of  heat  upon  them  ? 
I  answer,  Because  it  is  acting  upon  them  still ;  because  the 
earth  we  tread  is  but  a  thin  crust  floating  on  a  liquid  sea  of 
molten  materials ;  because  the  agencies  that  were  at  work  then 
are  at  work  now,  and  the  present  is  the  logical  sequence  of  the 
past.  From  artesian  wells,  from  mines,  from  geysers,  from  hot 
springs,  a  mass  of  facts  has  been  collected,  proving  incontesta- 
bly  the  heated  condition  of  all  substances  at  a  certain  depth 
below  the  earth's  surface ;  and  if  we  need  more  positive  evi- 
dence, we  have  it  in  the  fiery  eruptions  that  even  now  bear 
fearful  testimony  to  the  molten  ocean  seething  within  the  globe 
and  forcing  its  way  out  from  time  to  time.  The  modern  prog- 
ress of  geology  has  led  us  by  successive  and  perfectly  con- 
nected steps  back  to  a  time  when  what  is  now  only  an  occa- 
sional and  rare  phenomenon  was  the  normal  condition  of  our 
earth ;  when  the  internal  fires  were  enclosed  by  an  envelope  so 
thin  that  it  opposed  but  little  resistance  to  their  frequent  out- 
break, and  they  constantly  forced  themselves  through  this  crust, 
pouring  out  melted  materials  that  subsequently  cooled  and  con- 
solidated on  its  surface.  So  constant  were  these  eruptions, 
and  so  slight  was  the  resistance  they  encountered,  that  some 
portions  of  the  earlier  rock-deposits  are  perforated  with  numer- 
ous chimneys,  narrow  tunnels  as  it  were,  bored  by  the  liquid 
masses  that  poured  out  through  them  and  greatly  modified 
their  first  condition. 

The  question  at  once  suggests  itself,  How  was  even  this 
thin  crust  formed  ?  what  should  cause  any  solid  envelope,  how- 


GEOLOGY  223 

ever  slight  and  filmy  when  compared  to  the  whole  bulk  of  the 
globe,  to  form  upon  the  surface  of  such  a  liquid  mass  ?  At  this 
point  of  the  investigation  the  geologist  must  appeal  to  the 
astronomer ;  for  in  this  vague  and  nebulous  border-land,  where 
the  very  rocks  lose  their  outlines  and  flow  into  each  other,  not 
yet  specialized  into  definite  forms  and  substances — there  the 
two  sciences  meet.  Astronomy  shows  us  our  planet  thrown 
off  from  the  central  mass  of  which  it  once  formed  a  part,  to  move 
henceforth  in  an  independent  orbit  of  its  own.  That  orbit,  it 
tells  us,  passed  through  celestial  spaces  cold  enough  to  chill 
this  heated  globe,  and  of  course  to  consolidate  it  externally. 
We  know,  from  the  action  of  similar  causes  on  a  smaller  scale 
and  on  comparatively  insignificant  objects  immediately  about 
us,  what  must  have  been  the  effect  of  this  cooling  process  upon 
the  heated  mass  of  the  globe.  All  substances  when  heated 
occupy  more  space  than  they  do  when  cold.  Water,  which  ex- 
pands when  freezing,  is  the  only  exception  to  this  rule.  The 
first  effect  of  cooling  the  surface  of  our  planet  must  have  been 
to  solidify  it,  and  thus  to  form  a  film  or  crust  over  it.  That 
crust  would  shrink  as  the  cooling  process  went  on ;  in  conse- 
quence of  the  shrinking,  wrinkles  and  folds  would  arise  upon  it, 
and  here  and  there,  where  the  tension  was  too  great,  cracks 
and  fissures  would  be  produced.  In  proportion  as  the  surface 
cooled,  the  masses  within  would  be  affected  by  the  change  of 
temperature  outside  of  them,  and  would  consolidate  internally 
also,  the  crust  gradually  thickening  by  this  process. 

But  there  was  another  element  without  the  globe,  equally 
powerful  in  building  it  up.  Fire  and  water  wrought  together 
in  this  work,  if  not  always  harmoniously,  at  least  with  equal 
force  and  persistency.  I  have  said  that  there  was  a  time  when 
no  atmosphere  surrounded  the  earth ;  but  one  of  the  first  re- 
sults of  the  cooling  of  its  crust  must  have  been  the  formation 
of  an  atmosphere,  with  all  the  phenomena  connected  with  it — 
the  rising  of  vapors,  their  condensation  into  clouds,  the  falling 
of  rains,  the  gathering  of  waters  upon  its  surface.  Water  is  a 
very  active  agent  of  destruction,  but  it  works  over  again  the 
materials  it  pulls  down  or  wears  away,  and  builds  them  up  anew 
in  other  forms.  A.S  soon  as  an  ocean  washed  over  the  consoli- 


224  ACHIEVEMENTS  IN  SCIENCE 

dated  crust  of  the  globe,  it  would  begin  to  abrade  the  surfaces 
upon  which  it  moved,  gradually  loosening  and  detaching  mate- 
rials, to  deposit  them  again  as  sand  or  mud  or  pebbles  at  its 
bottom  in  successive  layers,  one  above  another.  Thus,  in  ana- 
lyzing the  crust  of  the  globe,  we  find  at  once  two  kinds  of 
rocks,  the  respective  work  of  fire  and  water :  the  first  poured 
out  from  the  furnaces  within,  and  cooling,  as  one  may  see  any 
mass  of  metal  cool  that  is  poured  out  from  a  smelting-furnace 
to-day,  in  solid  crystalline  masses,  without  any  division  into 
separate  layers  or  leaves ;  and  the  latter  in  successive  beds,  one 
over  another,  the  heavier  materials  below,  the  lighter  above,  or 
sometimes  in  alternate  layers,  as  special  causes  may  have  deter- 
mined successive  deposits  of  lighter  or  heavier  materials  at 
some  given  spot. 

There  were  many  well-fought  battles  between  geologists 
before  it  was  understood  that  these  two  elements  had  been 
equally  active  in  building  up  the  crust  of  the  earth.  The 
ground  was  hotly  contested  by  the  disciples  of  the  two  geologi- 
cal schools,  one  of  which  held  that  the  solid  envelope  of  the 
earth  was  exclusively  due  to  the  influence  of  fire,  while  the 
other  insisted  that  it  had  been  accumulated  wholly  under  the 
agency  of  water.  This  difference  of  opinion  grew  up  very 
naturally ;  for  the  great  leaders  of  the  two  schools  lived  in  dif- 
ferent localities,  and  pursued  their  investigations  over  regions 
where  the  geological  phenomena  were  of  an  entirely  opposite 
character — the  one  exhibiting  the  effect  of  volcanic  eruptions, 
the  other  that  of  stratified  deposits.  It  was  the  old  story  of 
the  two  knights  on  opposite  sides  of  the  shield,  one  swearing 
that  it  was  made  of  gold,  the  other  that  it  was  made  of  silver, 
and  almost  killing  each  other  before  they  discovered  that  it  was 
made  of  both.  So  prone  are  men  to  hug  their  theories  and 
shut  their  eyes  to  any  antagonistic  facts,  that  it  is  related  of 
Werner,  the  great  leader  of  the  Aqueous  school,  that  he  was 
actually  on  his  way  to  see  a  geological  locality  of  especial  inter- 
est, but,  being  told  that  it  confirmed  the  views  of  his  opponents, 
he  turned  round  and  went  home  again,  refusing  to  see  what 
might  force  him  to  change  his  opinions.  If  the  rocks  did  not 
confirm  his  theory,  so  much  the  worse  for  the  rocks — he  would 


GEOLOGY  225 

none  of  them.  At  last  it  was  found  that  the  two  great  chem- 
ists, fire  and  water,  had  worked  together  in  the  vast  laboratory 
of  the  globe,  and  since  then  scientific  men  have  decided  to 
work  together  also ;  and  if  they  still  have  a  passage  at  arms 
occasionally  over  some  doubtful  point,  yet  the  results  of  their 
investigations  are  ever  drawing  them  nearer  to  each  other — 
since  men  who  study  truth,  when  they  reach  their  goal,  must 
always  meet  at  last  on  common  ground. 

The  rocks  formed  under  the  influence  of  heat  are  called,  in 
geological  language,  the  Igneous,  or,  as  some  naturalists  have 
named  them,  the  Plutonic  rocks,  alluding  to  their  fiery  origin, 
while  the  others  have  been  called  Aqueous  or  Neptunic  rocks, 
in  reference  to  their  origin  under  the  agency  of  water.  A  sim- 
pler term,  however,  quite  as  distinctive,  and  more  descriptive 
of  their  structure,  is  that  of  the  stratified  and  massive  or  un- 
stratified  rocks.  We  shall  see  hereafter  how  the  relative  posi- 
tion of  these  two  classes  of  rocks  and  their  action  upon  each 
other  enable  us  to  determine  the  chronology  of  the  earth,  to 
compare  the  age  of  her  mountains,  and,  if  we  have  no  standard 
by  which  to  estimate  the  positive  duration  of  her  continents,  to 
say  at  least  which  was  the  first-born  among  them,  and  how 
their  characteristic  features  have  been  successfully  worked  out. 
I  am  aware  that  many  of  these  inferences,  drawn  from  what  is 
called  "the  geological  record,"  must  seem  to  be  the  work  of 
the  imagination.  In  a  certain  sense  this  is  true — for  imagina- 
tion, chastened  by  correct  observation,  is  our  best  guide  in  the 
study  of  Nature.  We  are  too  apt  to  associate  the  exercise  of 
this  faculty  with  works  of  fiction,  while  it  is  in  fact  the  keenest 
detective  of  truth. 

Besides  the  stratified  and  massive  rocks,  there  is  still  a  third 
set,  produced  by  the  contact  of  these  two,  and  called,  in  conse- 
quence of  the  changes  thus  brought  about,  the  Metamorphic 
rocks.  The  effect  of  heat  upon  clay  is  to  bake  it  into  slate ; 
limestone  under  the  influence  of  heat  becomes  quicklime,  or, 
if  subjected  afterward  to  the  action  of  water,  it  is  changed  to 
mortar ;  sand  under  the  same  agency  is  changed  to  a  coarse 
kind  of  glass.  Suppose,  then,  that  a  volcanic  eruption  takes 
place  in  a  region  of  the  earth's  surface  where  successive  layers 


226  ACHIEVEMENTS  IN  SCIENCE 

of  limestone,  of  clay,  and  of  sandstone  have  been  previously 
deposited  by  the  action  of  water.  If  such  an  eruption  has 
force  enough  to  break  through  these  beds,  the  hot,  melted 
masses  will  pour  out  through  the  rent,  flow  over  its  edges,  and 
fill  all  the  lesser  cracks  and  fissures  produced  by  such  a  distur- 
bance. What  will  be  the  effect  upon  the  stratified  rocks? 
Wherever  these  liquid  masses,  melted  by  a  heat  more  intense 
than  can  be  produced  by  any  artificial  means,  have  flowed  over 
them  or  cooled  in  immediate  contact  with  them,  the  clays  will 
be  changed  to  slate,  the  limestone  will  have  assumed  a  charac- 
ter more  like  marble,  while  the  sandstone  will  be  vitrified. 
This  is  exactly  what  has  been  found  to  be  the  case,  wherever 
the  stratified  rocks  have  been  penetrated  by  the  melted  masses 
from  beneath.  They  have  been  themselves  partially  melted 
by  the  contact,  and  when  they  have  cooled  again,  their  stratifi- 
cation, though  still  perceptible,  has  been  partly  obliterated,  and 
their  substance  changed.  Such  effects  may  often  be  traced  in 
dikes,  which  are  only  the  cracks  in  rocks  filled  by  materials 
poured  into  them  at  some  period  of  eruption  when  the  melted 
masses  within  the  earth  were  thrown  out  and  flowed  like  water 
into  any  inequality  or  depression  of  the  surface  around.  The 
walls  enclosing  such  a  dike  are  often  found  to  be  completely 
altered  by  contact  with  its  burning  contents,  and  to  have 
assumed  a  character  quite  different  from  the  rocks  of  which 
they  make  a  part ;  while  the  mass  itself  which  fills  the  fissure 
shows  by  the  character  of  its  crystallization  that  it  has  cooled 
more  quickly  on  the  outside,  where  it  meets  the  walls,  than  at 
the  center. 

The  first  two  great  classes  of  rocks,  the  unstratified  and 
stratified  rocks,  represent  different  epochs  in  the  world's  physi- 
cal history :  the  former  mark  its  revolutions,  while  the  latter 
chronicle  its  periods  of  rest.  All  mountains  and  mountain- 
chains  have  been  upheaved  by  great  convulsions  of  the  globe, 
which  rent  asunder  the  surface  of  the  earth,  destroyed  the  ani- 
mals and  plants  living  upon  it  at  the  time,  and  were  then  suc- 
ceeded by  long  intervals  of  repose,  when  all  things  returned  to 
their  accustomed  order,  ocean  and  river  deposited  fresh  beds  in 
uninterrupted  succession,  the  accumulation  of  materials  went 


GEOLOGY  227 

on  as  before,  a  new  set  of  animals  and  plants  were  introduced, 
and  a  time  of  building  up  and  renewing  followed  the  time  of 
destruction.  These  periods  of  revolution  are  naturally  more 
difficult  to  decipher  than  the  periods  of  rest ;  for  they  have  so 
torn  and  shattered  the  beds  they  uplifted,  disturbing  them 
from  their  natural  relations  to  each  other,  that  it  is  not  easy  to 
reconstruct  the  parts  and  give  them  coherence  and  complete- 
ness again.  But  within  the  last  half -century  this  work  has  been 
accomplished  in  many  parts  of  the  world  with  an  amazing  de- 
gree of  accuracy,  considering  the  disconnected  character  of  the 
phenomena  to  be  studied ;  and  I  think  I  shall  be  able  to  con- 
vince my  readers  that  the  modern  results  of  geological  investi- 
gation are  perfectly  sound  logical  inferences  from  well-estab- 
lished facts.  In  this,  as  in  so  many  other  things,  we  are  but 
"children  of  a  larger  growth."  The  world  is  the  geologist's 
great  puzzle-box ;  he  stands  before  it  like  the  child  to  whom  the 
separate  pieces  of  his  puzzle  remain  a  mystery  till  he  detects 
their  relation  and  sees  where  they  fit,  and  then  his  fragments 
grow  at  once  into  a  connected  picture  beneath  his  hand.  .  .  . 

When  geologists  first  turned  their  attention  to  the  physical 
history  of  the  earth,  they  saw  at  once  certain  great  features 
which  they  took  to  be  the  skeleton  and  basis  of  the  whole 
structure.  They  saw  the  great  masses  of  granite  forming  the 
mountains  and  mountain-chains,  with  the  stratified  rocks  rest- 
ing against  their  slopes ;  and  they  assumed  that  granite  was 
the  first  primary  agent,  and  that  all  stratified  rocks  must  be  of 
a  later  formation.  Although  this  involved  a  partial  error,  as 
we  shall  see  hereafter  when  we  trace  the  upheavals  of  granite 
even  into  comparatively  modern  periods,  yet  it  held  an  impor- 
tant geological  truth  also;  for,  though  granite  formations  are 
by  no  means  limited  to  those  early  periods,  they  are  neverthe- 
less very  characteristic  of  them,  and  are  indeed  the  foundation- 
stones  on  which  the  physical  history  of  the  globe  is  built. 

Starting  from  this  landmark,  the  earlier  geologists  divided 
the  world's  history  into  three  periods.  As  the  historian  recog- 
nizes Ancient  History,  the  Middle  Ages,  and  Modern  History, 
as  distinct  phases  in  the  growth  of  the  human  race,  so  they  dis- 
tinguished between  what  they  called  the  Primary  period,  when, 


228  ACHIEVEMENTS  IN  SCIENCE 

as  they  believed,  no  life  stirred  on  the  surface  of  the  earth ;  the 
Secondary  or  Middle  period,  when  animals  and  plants  were  in- 
troduced, and  the  land  began  to  assume  continental  proportions ; 
and  the  Tertiary  period,  or  comparatively  modern  geological 
times,  when  the  physical  features  of  the  earth  as  well  as  its  in- 
habitants were  approaching  more  nearly  to  the  present  condi- 
tion of  things.  But  as  their  investigations  proceeded,  they 
found  that  every  one  of  these  great  ages  of  the  world's  history 
was  divided  into  numerous  lesser  epochs,  each  of  which  had 
been  characterized  by  a  peculiar  set  of  animals  and  plants,  and 
had  been  closed  by  some  great  physical  convulsion,  disturbing 
and  displacing  the  materials  accumulated  during  such  a  period 
of  rest. 

The  further  study  of  these  subordinate  periods  showed  that 
what  had  been  called  Primary  formations,  namely,  the  volcanic 
or  Plutonic  rocks  formerly  believed  to  be  confined  to  the  first 
geological  ages,  belonged  to  all  the  periods,  successive  erup- 
tions having  taken  place  at  all  times,  pouring  up  through  the 
accumulated  deposits  penetrating  and  injecting  their  cracks, 
fissures,  and  inequalities,  as  well  as  throwing  out  large  masses 
on  the  surface.  Up  to  our  own  day  there  has  never  been  a 
period  when  such  eruptions  have  not  taken  place,  though  they 
have  been  constantly  diminishing  in  frequency  and  extent.  In 
consequence  of  this  discovery,  that  rocks  of  igneous  character 
were  by  no  means  exclusively  characteristic  of  the  earliest 
times,  they  are  now  classified  together  upon  very  different 
grounds  from  those  on  which  geologists  first  united  them; 
though,  as  the  name  Primary  was  long  retained,  we  still  find 
it  applied  to  them,  even  in  geological  works  of  quite  recent 
date.  This  defect  of  nomenclature  is  to  be  regretted,  as  likely 
to  mislead  the  student,  because  it  seems  to  refer  to  time; 
whereas  it  no  longer  signifies  the  age  of  the  rocks,  but  simply 
their  character.  The  name  Plutonic  or  Massive  rocks  is,  how- 
ever, now  almost  universally  substituted  for  that  of  Primary. 

A  wide  field  of  investigation  still  remains  to  be  explored  b] 
the  chemist  and  the  geologist  together,  in  the  mineralogical 
character  of  the  Plutonic  rocks,  which  differs  greatly  in  the 
different  periods.  The  earlier  eruptions  seem  to  have  been 


GEOLOGY  229 

chiefly  granitic,  though  this  must  not  be  understood  in  too 
wide  a  sense  since  there  are  granite  formations  even  as  late  as 
the  Tertiary  period ;  those  of  the  middle  periods  were  mostly 
porphyries  and  basalts ;  while  in  the  more  recent  ones  lavas 
predominate.  We  have  as  yet  no  clew  to  the  laws  by  which 
this  distribution  of  volcanic  elements  in  the  formation  of  the 
earth  is  regulated ;  but  there  is  found  to  be  a  difference  in  the 
crystals  of  the  Plutonic  rocks  belonging  to  different  ages,  which, 
when  fully  understood,  may  enable  us  to  determine  the  age  of 
any  Plutonic  rock  by  its  mode  of  crystallization ;  so  that  the 
mineralogist  will  as  readily  tell  you  by  its  crystals  whether  a 
bit  of  stone  of  igneous  origin  belongs  to  this  or  that  period  of 
the  world's  history,  as  the  palaeontologist  will  tell  you  by  its 
fossils  whether  a  piece  of  rock  of  aqueous  origin  belongs  to  the 
Silurian  or  Devonian  or  Carboniferous  deposits. 


GEOLOGY 

Composition  and  Material  of  the  Earth's 

Crust 

By  AGNES  GIBERNE 

WHAT  is  the  earth  made  of — this  round  earth  upon  whi< 
we  human  beings  live  and  move  ? 

A  question  more  easily  asked  than  answered,  as  regards 
very  large  portion  of  it.  For  the  earth  is  a  huge  ball  nearly 
eight  thousand  miles  in  diameter,  and  we  who  dwell  on  the  out- 
side have  no  means  of  getting  down  more  than  a  very  little 
way  below  the  surface.  So  it  is  quite  impossible  for  us  to 
speak  positively  as  to  the  inside  of  the  earth,  and  what  it  is 
made  of.  Some  people  believe  the  earth's  inside  to  be  hard  and 
solid,  while  others  believe  it  to  be  one  enormous  lake  or  furnace 
of  fiery  melted  rock.  But  nobody  really  knows. 

This  outside  crust  has  been  reckoned  to  be  of  many  differ- 
ent thicknesses.  One  man  will  say  it  is  ten  miles  thick,  and 
another  will  rate  it  at  four  hundred  miles.  So  far  as  regards 
man's  knowledge  of  it,  gained  from  mining,  from  boring,  from 
examination  of  rocks,  and  from  reasoning  out  all  that  may  be 
learned  from  these  observations,  we  shall  allow  an  ample  mar- 
gin if  we  count  the  field  of  geology  to  extend  some  twenty  miles 
downwards  from  the  highest  mountain-tops.  Beyond  this  we 
find  ourselves  in  a  land  of  darkness  and  conjecture. 

Twenty  miles  is  only  one  four-hundredth  part  of  the  earth's 
diameter — a  mere  thin  shell  over  a  massive  globe.  If  the  earth 
were  brought  down  in  size  to  an  ordinary  large  school  globe,  a 
piece  of  rough  brown  paper  covering  it  might  well  represent 

230 


GEOLOGY  231 

the  thickness  of  this  earth-crust,  with  which  the  science  of 
geology  has  to  do.  And  the  whole  of  the  globe,  this  earth  of 
ours,  is  but  one  tiny  planet  in  the  great  Solar  System. 
And  the  center  of  that  Solar  System,  the  blazing  sun,  though 
equal  in  size  to  more  than  a  million  earths,  is  yet  himself  but 
one  star  amid  millions  of  twinkling  stars,  scattered  broadcast 
through  the  universe.  So  it  would  seem  at  first  sight  that  the 
field  of  geology  is  a  small  field  compared  with  that  of  astron- 
omy  

With  regard  to  the  great  bulk  of  the  globe  little  can  be  said. 
Very  probably  it  is  formed  through  and  through  of  the  same 
materials  as  the  crust.  This  we  do  not  know.  Neither  can 
we  tell,  even  if  it  be  so  formed,  whether  the  said  materials  are 
solid  and  cold  like  the  outside  crust,  or  whether  they  are  liquid 
with  heat.  The  belief  has  been  long  and  widely  held  that  the 
whole  inside  of  the  earth  is  one  vast  lake  or  furnace  of  melted 
fiery-hot  material,  with  only  a  thin  cooled  crust  covering  it. 
Some  in  the  present  day  are  inclined  to  question  this,  and  hold 
rather  that  the  earth  is  solid  and  cold  throughout,  though  with 
large  lakes  of  liquid  fire  here  and  there,  under  or  in  the  crust, 
from  which  our  volcanoes  are  fed.  .  .  . 

The  materials  of  which  the  crust  is  made  are  many  and 
various;  yet,  generally  speaking,  they  may  all  be  classed  under 
one  simple  word,  and  that  word  is — Rock. 

It  must  be  understood  that,  when  we  talk  of  rock  in  this 
geological  sense,  we  do  not  only  mean  hard  and  solid  stone,  as 
in  common  conversation.  Rock  may  be  changed  by  heat  into 
a  liquid  or  "  molten  "  state,  as  ice  is  changed  by  heat  to  water. 
Liquid  rock  may  be  changed  by  yet  greater  heat  to  vapor,  as 
water  is  changed  to  steam,  only  we  have  in  a  common  way  no 
such  heat  at  command  as  would  be  needed  to  effect  this.  Rock 
may  be  hard  or  soft.  Rock  may  be  chalky,  clayey,  or  sandy. 
Rock  may  be  so  close-grained  that  strong  force  is  needed  to 
break  it ;  or  it  may  be  so  porous — so  full  of  tiny  holes — that 
water  will  drain  through  it ;  or  it  may  be  crushed  and  crumbled 
into  loose  grains,  among  which  you  can  pass  your  fingers. 

The  cliffs  above  our  beaches  are  rock ;  the  sand  upon  our 
seashore  is  rock ;  the  clay  used  in  brick-making  is  rock ;  the 


232  ACHIEVEMENTS  IN  SCIENCE 

limestone  of  the  quarry  is  rock;  the  marble  of  which  our 
mantel-pieces  are  made  is  rock.  The  soft  sandstone  of  South 
Devon,  and  the  hard  granite  of  the  north  of  Scotland,  are  alike 
rock.  The  pebbles  in  the  road  are  rock ;  the  very  mold  in  our 
gardens  is  largely  composed  of  crumbled  rock.  So  the  word  in 
its  geological  sense  is  a  word  of  wide  meaning. 

Now  the  business  of  the  geologist  is  to  read  the  history  of 
the  past  in  these  rocks  of  which  the  earth's  crust  is  made. 

Rocks  may  be  divided  into  several  kinds  or  classes.  For 
the  present  moment  it  will  be  enough  to  consider  the  two 
grand  divisions — Stratified  Rocks  and  Unstratified  Rocks. 

Unstratified  rocks  are  those  which  were  once,  at  a  time 
more  or  less  distant,  in  a  melted  state  from  intense  heat,  and 
which  have  since  cooled  into  a  half  crystallized  state ;  much 
the  same  as  water,  when  growing  colder,  cools  and  crystallizes 
into  ice.  Strictly  speaking  ice  is  rock,  just  as  much  as  granite 
and  sandstone  are  rock.  Water  itself  is  of  the  nature  of  rock, 
only  as  we  commonly  know  it  in  the  liquid  state  we  do  not 
commonly  call  it  so. 

"  Crystallization"  means  those  particular  forms  or  shapes  in 
which  the  particles  of  a  liquid  arrange  themselves,  as  that  liquid 
hardens  into  a  solid — in  other  words,  as  it  freezes.  Granite, 
iron,  marble,  are  frozen  substances,  just  as  truly  as  ice  is  a 
frozen  substance ;  for  with  greater  heat  they  would  all  become 
liquid  like  water.  When  a  liquid  freezes,  there  are  always  crys- 
tals formed,  though  these  are  not  always  visible  without  the 
help  of  a  microscope.  Also  the  crystals  are  of  different  shapes 
with  different  substances. 

If  you  examine  the  surface  of  a  puddle  or  pond,  when  a  thin 
covering  of  ice  is  beginning  to  form,  you  will  be  able  to  see 
plainly  the  delicate,  sharp,  needle-like  forms  of  the  ice  crystals. 
Break  a  piece  of  ice,  and  you  will  find  that  it  will  not  easily 
break  just  in  any  way  that  you  may  choose,  but  it  will  only 
split  along  the  lines  of  these  needle-like  crystals.  This  particu- 
lar mode  of  splitting  in  a  crystallized  rock  is  called  the  cleavage 
of  that  rock. 

Crystallization  may  take  place  either  slowly  or  rapidly,  and 
either  in  the  open  air  or  far  below  ground.  The  lava  from  a 


GEOLOGY  233 

volcano  is  an  example  of  rock  which  has  crystallized  rapidly  in 
the  open  air ;  and  granite  is  an  example  of  rock  which  has  crys- 
tallized slowly  underground  beneath  great  pressure. 

Stratified  rocks,  on  the  contrary,  which  make  up  a  very 
large  part  of  the  earth's  crust,  are  not  crystallized.  Instead  of 
having  cooled  from  a  liquid  into  a  solid  state,  they  have  been 
slowly  built  up,  bit  by  bit  and  grain  upon  grain,  into  their  pres- 
ent form,  through  long  ages  of  the  world's  history.  The  mate- 
rials of  which  they  are  made  were  probably  once,  long,  long 
ago,  the  crumblings  from  granite  and  other  crystallized  rocks, 
but  they  show  now  no  signs  of  crystallization. 

They  are  called  "  stratified  "  because  they  are  in  themselves 
made  up  of  distinct  layers,  and  also  because  they  lie  thus  one 
upon  another  in  layers,  or  strata,  just  as  the  leaves  of  a  book 
lie,  or  as  the  bricks  of  a  house  are  placed. 

Throughout  the  greater  part  of  Europe,  of  Asia,  of  Africa, 
of  North  and  South  America,  of  Australia,  these  rocks  are  to 
be  found,  stretching  over  hundreds  of  miles  together,  north, 
south,  east,  and  west,  extending  up  to  the  tops  of  some  of  the 
earth's  highest  mountains,  reaching  down  deep  into  the  earth's 
crust.  In  many  parts  if  you  could  dig  straight  downward 
through  the  earth  for  thousands  of  feet,  you  would  come  to 
layer  after  layer  of  these  stratified  rocks,  one  kind  below 
another,  some  layers  thick,  some  layers  thin,  here  a  stratum  of 
gravel,  there  a  stratum  of  sandstone,  here  a  stratum  of  coal, 
there  a  stratum  of  clay. 

But  how,  when,  where,  did  the  building  up  of  all  these  rock- 
layers  take  place  ? 

People  are  rather  apt  to  think  of  land  and  water  on  the 
earth  as  if  they  were  fixed  in  one  changeless  form — as  if  every 
continent  and  every  island  were  of  exactly  the  same  shape  and 
size  now  that  it  always  has  been  and  always  will  be. 

Yet  nothing  can  be  further  from  the  truth.  The  earth- 
crust  is  a  scene  of  perpetual  change,  of  perpetual  struggle,  of 
perpetual  building  up,  of  perpetual  wearing  away. 

The  work  may  go  on  slowly,  but  it  does  go  on.  The  sea  is 
always  fighting  against  the  land,  beating  down  her  cliffs,  eating 
into  her  shores,  swallowing  bit  by  bit  of  solid  earth ;  and  rain 


2-34  ACHIEVEMENTS  IN  SCIENCE 

and  frost  and  inland  streams  are  always  busily  at  work,  helping 
the  ocean  in  her  work  of  destruction.  Year  by  year  and  cen- 
tury by  century  it  continues.  Not  a  country  in  the  world 
which  is  bordered  by  the  open  sea  has  precisely  the  same  coast- 
line that  it  had  one  hundred  years  ago ;  not  a  land  in  the  world 
but  parts  each  century  with  masses  of  its  material,  washed 
piecemeal  away  into  the  ocean. 

See  the  effect  upon  the  beach  of  one  night's  fierce  storm. 
Mark  the  pathway  on  the  cliff,  how  it  seems  to  have  crept  so 
near  the  edge  that  here  and  there  it  is  scarcely  safe  to  tread ; 
and  very  soon,  as  we  know,  it  will  become  impassable.  Just 
from  a  mere  accident,  of  course — the  breaking  away  of  some  of 
the  earth,  loosened  by  rain  and  frost  and  wind.  But  this  is  an 
accident  which  happens  daily  in  hundreds  of  places  around  the 
shores. 

Leaving  the  ocean,  look  now  at  this  river  in  our  neighbor- 
hood, and  see  the  slight  muddiness  which  seems  to  color  its 
waters.  What  from  ?  Only  a  little  earth  and  sand  carried  off 
from  the  banks  as  it  flowed — very  unimportant  and  small  in 
quantity,  doubtless,  just  at  this  moment  and  just  at  this  spot. 
But  what  of  that  little  going  on  week  after  week,  and  century 
after  century,  throughout  the  whole  course  of  the  river,  and 
throughout  the  whole  course  of  every  river  and  rivulet  in  our 
whole  country  and  in  every  other  country  ?  A  vast  amount  of 
material  must  every  year  be  thus  torn  from  the  land  and  given 
to  the  ocean.  For  the  land's  loss  here  is  the  ocean's  gain. 

And,  strange  to  say,  we  shall  find  that  this  same  ocean,  so 
busily  engaged  with  the  help  of  its  tributary  rivers  in  pulling 
down  land,  is  no  less  busily  engaged  with  their  help  in  building 
it  up. 

You  have  sometimes  seen  directions  upon  a  vial  of  medicine 
to  "  shake  "  before  taking  the  dose.  When  you  have  so  shaken 
the  bottle  the  clear  liquid  grows  thick ;  and  if  you  let  it  stand 
for  a  while  the  thickness  goes  off,  and  a  fine  grain-like  or  dust- 
like  substance  settles  down  at  the  bottom — the  settlement  or 
sediment  of  the  medicine.  The  finer  this  sediment,  the  slower 
it  is  in  settling.  If  you  were  to  keep  the  liquid  in  gentle  mo- 
tion the  fine  sediment  would  not  settle  down  at  the  bottom. 


GEOLOGY  235 

With  coarser  and  heavier  grains  the  motion  would  have  to  be 
quicker  to  keep  them  supported  in  the  water. 

Now  it  is  just  the  same  thing  with  our  rivers  and  streams. 
Running  water  can  support  and  carry  along  sand  and  earth, 
which  in  still  water  would  quickly  sink  to  the  bottom ;  and  the 
more  rapid  the  movement  of  the  water,  the  greater  is  the 
weight  it  is  able  to  bear. 

This  is  plainly  to  be  seen  in  the  case  of  a  mountain  torrent. 
As  it  foams  fiercely  through  its  rocky  bed  it  bears  along,  not 
only  mud  and  sand  and  gravel,  but  stones  and  even  small  rocks, 
grinding  the  latter  roughly  together  till  they  are  gradually 
worn  away,  first  to  rounded  pebbles,  then  to  sand,  and  finally 
to  mud.  The  material  thus  swept  away  by  a  stream,  ground 
fine,  and  carried  out  to  sea — part  being  dropped  by  the  way  on 
the  river-bed — is  called  detritus,  which  simply  means  worn-out 
material. 

The  tremendous  carrying-power  of  a  mountain  torrent  can 
scarcely  be  realized  by  those  who  have  not  observed  it  for  them- 
selves. I  have  seen  a  little  mountain-stream  swell  in  the  course 
of  a  heavy  thunder-storm  to  such  a  torrent,  brown  and  turbid 
with  earth  torn  from  the  mountain-side,  and  sweeping  resist- 
lessly  along  in  its  career  a  shower  of  stones  and  rock-fragments. 
That  which  happens  thus  occasionally  with  many  streams  is 
more  or  less  the  work  all  the  year  round  of  many  more. 

As  the  torrent  grows  less  rapid,  lower  down  in  its  course,  it 
ceases  to  carry  rocks  and  stones,  though  the  grinding  and  wear- 
ing away  of  stones  upon  the  rocky  bed  continue,  and  coarse 
gravel  is  borne  still  upon  its  waters.  Presently  the  widening 
stream,  flowing  yet  more  calmly,  drops  upon  its  bed  all  such 
coarser  gravel  as  is  not  worn  away  to  fine  earth,  but  still  bears 
on  the  lighter  grains  of  sand.  Next  the  slackening  speed 
makes  even  the  sand  too  heavy  a  weight,  and  that  in  turn  falls 
to  line  the  river-bed,  while  the  now  broad  and  placid  stream 
carries  only  the  finer  particles  of  mud  suspended  in  its  waters. 
Soon  it  reaches  the  ocean,  and  the  flow  being  there  checked  by 
the  incoming  ocean-tide,  even  the  mud  can  no  longer  be  held 
up,  and  it  also  sinks  slowly  in  the  shallows  near  the  shore, 
forming  sometimes  broad  mud-banks  dangerous  to  the  mariner. 


236  ACHIEVEMENTS  IN  SCIENCE 

This  is  the  case  only  with  smaller  rivers.  Where  the 
stream  is  stronger,  the  mud-banks  are  often  formed  much 
farther  out  at  sea;  and  more  often  still  the  river-detritus  is 
carried  away  and  shed  over  the  ocean-bed,  beyond  the  reach 
of  our  ken.  The  powerful  rush  of  water  in  earth's  greater 
streams  bears  enormous  masses  of  sand  and  mud  each  year  far 
out  into  the  ocean,  there  dropping  quietly  the  gravel,  sand,  and 
earth,  layer  upon  layer  at  the  bottom  of  the  sea.  Thus  pulling 
down  and  building  up  go  on  ever  side  by  side ;  and  while  land 
is  the  theater  oftentimes  of  decay  and  loss,  ocean  is  the  theater 
oftentimes  of  renewal  and  gain. 

Did  you  notice  the  word  "  sediment  "  used  a  few  pages  back 
about  the  settlement  at  the  bottom  of  a  medicine-vial  ? 

There  is  a  second  name  given  to  the  stratified  rocks,  of 
which  the  earth's  crust  is  so  largely  made  up.  They  are  called 
also  Sedimentary  Rocks. 

The  reason  is  simply  this.  The  stratified  rocks  of  the 
present  day  were  once  upon  a  time  made  up  out  of  the  sedi- 
ment stolen  first  from  land  and  then  allowed  to  settle  down  on 
the  sea-bottom. 

Long,  long  ago,  the  rivers,  the  streams,  the  ocean,  were  at 
work,  as  they  are  now,  carrying  away  rock  and  gravel,  sand  and 
earth.  Then,  as  now,  all  this  material,  borne  upon  the  rivers, 
washed  to  and  fro  by  the  ocean,  settled  down  at  the  mouths  of 
rivers  or  at  the  bottom  of  the  sea,  into  a  sediment,  one  layer 
forming  up  over  another,  gradually  built  up  through  long  ages. 
At  first  it  was  only  a  soft,  loose,  sandy  or  muddy  sediment, 
such  as  you  may  see  on  the  seashore,  or  in  a  mud-bank.  But 
as  the  thickness  of  the  sediment  increased,  the  weight  of  the 
layers  above  gradually  pressed  the  lower  layers  into  firm  hard 
rocks ;  and  still,  as  the  work  of  building  went  on,  these  layers 
were,  in  their  turn,  made  solid  by  the  increasing  weight  over 
them.  Certain  chemical  changes  had  also  a  share  in  the  trans- 
formation from  soft  mud  to  hard  rock,  which  need  not  be  here 
considered. 

All  this  has  through  thousands  of  years  been  going  on. 
The  land  is  perpetually  crumbling  away  and  fresh  land  under 


GEOLOGY  237 

the  sea  is  being  perpetually  built  up,  from  the  very  same  mate- 
rials which  the  sea  and  the  rivers  have  so  mercilessly  stolen 
from  continents  and  islands.  This  is  the  way,  if  geologists 
rightly  judge,  in  which  a  very  large  part  of  the  enormous 
formations  of  stratified  or  sedimentary  rocks  have  been 
made. 

So  far  is  clear.     But  now  we  come  to  a  difficulty. 

The  stratified  rocks,  of  which  a  very  large  part  of  the 
continents  is  made,  appear  to  have  been  built  up  slowly,  layer 
upon  layer,  out  of  the  gravel,  sand,  and  mud,  washed  away  from 
the  land  and  dropped  on  the  shore  of  the  ocean. 

You  may  see  these  layers  for  yourself  as  you  walk  out  into 
the  country.  Look  at  the  first  piece  of  bluff  rock  you  come 
near,  and  observe  the  clear  pencil-like  markings  of  layer  above 
layer — not  often  indeed  ly'mgjlat,  one  over  another,  and  this 
must  be  explained  later,  but,  however  irregularly  slanting,  still 
plainly  visible.  You  can  examine  these  lines  of  stratification 
on  the  nearest  cliff,  the  nearest  quarry,  the  nearest  bare  head- 
land, in  your  neighborhood. 

But  how  can  this  be  ?  If  all  these  stratified  rocks  are  built 
on  the  floor  of  the  ocean  out  of  material  taken  from  the  land, 
how  can  we  by  any  possibility  find  such  rocks  tipon  the  land  ? 
In  the  beds  of  rivers  we  might  indeed  expect  to  see  them,  but 
surely  nowhere  else  save  under  ocean  waters. 

Yet  find  them  we  do.  Through  the  two  great  world-conti- 
nents, they  abound  on  every  side.  Thousands  of  miles  in  un- 
broken succession  are  composed  of  such  rocks. 

Stand  with  me  near  the  seashore,  and  let  us  look  around. 
See,  in  the  rough  sides  of  yonder  bluff  the  markings  spoken  of, 
fine  lines  running  alongside  of  one  another,  sometimes  flat, 
sometimes  bent  or  slanting,  but  always  giving  the  impression 
of  layer  piled  upon  layer.  Yet  how  can  one  for  a  moment  sup- 
pose that  the  ocean-waters  ever  rose  so  high  ?  Look  again  at 
yonder  cliff,  and  observe  a  little  way  below  the  top  a  singular 
band  of  shingles,  squeezed  into  the  cliff,  as  it  were,  with  chalk 
below  and  earth  above. 

That  is  believed  to  be  an  old  sea-beach.  Once  upon  a  time 
the  waters  of  the  sea  are  supposed  to  have  washed  those  shin- 


238  ACHIEVEMENTS  IN  SCIENCE 

gles,  as  now  they  wash  the  shore  near  which  we  stand,  and  all 
the  white  cliff  must  have  lain  then  beneath  the  ocean. 

Geologists  were  for  a  long  while  sorely  puzzled  to  account 
for  these  old  sea-beaches,  found  high  up  in  the  cliffs  around  our 
land  in  many  different  places. 

They  had  at  first  a  theory  that  the  sea  must  once,  in  far 
back  ages,  have  been  a  great  deal  higher  than  it  is  now.  But 
this  explanation  only  brought  about  fresh  difficulties.  It  is 
quite  impossible  that  the  level  of  the  sea  should  be  higher  in 
one  part  of  the  world  than  in  another.  Besides,  in  some  places 
remains  of  sea-animals  are  found  in  mountain  heights,  as  much 
as  two  or  three  thousand  feet  above  the  sea-level — as,  for  in- 
stance, in  Corsica.  This  very  much  increases  the  difficulty  of 
the  above  explanation. 

So  another  theory  was  started  instead,  and  this  is  now  gen- 
erally supposed  to  be  the  true  one.  What  if,  instead  of  the 
whole  ocean  having  been  higher,  parts  of  the  land  were  lower  ? 
England  at  one  time,  parts  of  Europe  at  another  time,  parts  of 
Asia  and  America  at  other  times,  may  have  slowly  sunk  be- 
neath the  ocean,  and  after  long  remaining  there  have  slowly 
risen  again. 

This  is  by  no  means  so  wild  a  supposition  as  it  may  seem 
when  first  heard,  and  as  it  doubtless  did  seem  when  first  pro- 
posed. For  even  in  the  present  day  these  movements  of  the 
solid  crust  of  our  earth  are  going  on.  The  coasts  of  Sweden 
and  Finland  have  long  been  slowly  and  steadily  rising  out  of 
the  sea,  so  that  the  waves  can  no  longer  reach  so  high  upon 
those  shores  as  in  years  gone  by  they  used  to  reach.  In  Green- 
land, on  the  contrary,  land  has  long  been  slowly  and  steadily 
sinking,  so  that  what  used  to  be  the  shore  now  lies  under  the 
sea.  Other  such  risings  and  sinkings  might  be  mentioned,  as 
also  many  more  in  connection  with  volcanoes  and  earthquakes, 
which  are  neither  slow  nor  steady,  but  sudden  and  violent. 

So  it  becomes  no  impossible  matter  to  believe  that,  in  the 
course  of  ages  past,  all  those  wide  reaches  of  our  continents 
and  islands,  where  sedimentary  rocks  are  to  be  found,  were 
each  in  turn,  at  one  time  or  another,  during  long  periods,  be- 
neath the  rolling  waters  of  the  ocean.  .  .  . 


GEOLOGY  239 

These  built-up  rocks  are  not  only  called  "  Stratified,"  and 
"  Sedimentary."  They  have  also  the  name  of  Aqueous  Rock, 
from  the  Latin  word  aqua,  water ;  because  they  are  believed  to 
have  been  formed  by  the  action  of  the  water. 

They  have  yet  another  and  fourth  title,  which  is  Fossilifer- 
ous  Rocks. 

Fossils  are  the  hardened  remains  of  animals  and  vegetables 
found  in  rocks.  They  are  rarely,  if  ever,  seen  in  unstratified 
rocks ;  but  many  layers  of  stratified  rocks  abound  in  these  re- 
mains. Whole  skeletons  as  well  as  single  bones,  whole  tree- 
trunks  as  well  as  single  leaves,  are  found  thus  embedded  in 
rock  layers,  where  in  ages  past  the  animal  or  plant  died  and 
found  a  grave.  They  exist  by  thousands  in  many  parts  of  the 
world,  varying  in  size  from  the  huge  skeleton  of  the  elephant 
to  the  tiny  shell  of  the  microscopic  animalcule. 

Fossils  differ  greatly  in  kind.  Sometimes  the  entire  shell 
or  bone  is  changed  into  stone,  losing  all  its  animal  substance, 
but  retaining  its  old  outline  and  its  natural  markings.  Some- 
times the  fossil  is  merely  the  hardened  impress  of  the  outside 
of  a  shell  or  leaf,  which  has  dented  its  picture  on  soft  clay,  and 
has  itself  disappeared,  while  the  soft  clay  has  become  rock,  and 
the  indented  picture  remains  fixed  through  after-centuries. 
Sometimes  the  fossil  is  the  cast  of  the  inside  of  a  shell ;  the 
said  shell  having  been  filled  with  soft  mud,  which  has  taken  its 
exact  shape  and  hardened,  while  the  shell  itself  has  vanished. 
The  most  complete  description  of  fossil  is  the  first  of  these 
three  kinds.  It  is  wonderfully  shown  sometimes  in  fossil  wood, 
where  all  the  tiny  cells  and  delicate  fibers  remain  distinctly 
marked  as  of  old,  only  the  whole  woody  substance  has  changed 
into  hard  stone. 

But  although  the  fossil  remains  of  quadrupeds  and  other 
land-animals  are  found  in  large  quantities,  their  number  is  small 
compared  with  the  enormous  number  of  fossil  sea-shells  and 
sea-animals. 

Land-animals,  as  a  rule,  have  been  so  preserved  only  when 
they  have  been  drowned  in  ponds  or  rivers,  or  mired  in  bogs 
and  swamps,  or  overtaken  by  frost  or  swept  out  to  sea. 

Sea-animals,  on  the  contrary,  have  been  so  preserved  on 


240  ACHIEVEMENTS  IN  SCIENCE 

land  whenever  that  land  has  been  under  the  sea ;  and  this  ap- 
pears to  have  been  the  case,  at  one  or  another  past  age,  with 
the  greater  part  of  our  present  continents.  These  fossil  re- 
mains of  sea  animals  are  discovered  in  all  quarters  of  the  world, 
not  only  on  the  seashore  but  also  far  inland,  not  only  deep  down 
underground  but  also  high  up  on  the  tops  of  lofty  mountains 
— a  plain  proof  that  over  the  summits  of  those  mountains  the 
ocean  must  once  have  rolled,  and  this  not  for  a  brief  space  only, 
but  through  long  periods  of  time.  And  not  on  the  mountain- 
summit  only  are  these  fossils  known  to  abound,  but  sometimes 
in  layer  below  layer  of  the  mountain,  from  top  to  bottom, 
through  thousands  of  feet  of  rock. 

This  may  well  seem  puzzling  at  first  sight.  Fossils  of  sea- 
creatures  on  a  mountain-top  are  startling  enough ;  yet  hardly 
so  startling  as  the  thought  of  fossils  inside  that  mountain. 
How  could  they  have  found  their  way  thither  ? 

The  difficulty  soon  vanishes,  if  once  we  clearly  understanc 
that  all  these  thousands  of  feet  of  rock  were  built  up  slowly, 
layer  after  layer,  when  portions  of  the  land  lay  deep  under  the 
sea.  Thus  each  separate  layer  of  mud  or  sand  or  other  mate- 
rial became  in  its  turn  the  top  layer,  and  was  for  the  time  the 
floor  of  the  ocean,  until  further  droppings  of  material  out  oi 
the  waters  made  a  fresh  layer,  covering  up  the  one  below. 

While  each  layer  was  thus  in  succession  the  top  layer  of  the 
building,  and  at  the  same  time  the  floor  of  the  ocean,  animals 
lived  and  died  in  the  ocean,  and  their  remains  sank  to  the  bot- 
tom, resting  upon  the  sediment  floor.  Thousands  of  such  dead 
remains  disappeared,  crumbling  into  fine  dust  and  mingling 
with  the  waters,  but  here  and  there  one  was  caught  captive  by 
the  half-liquid  mud,  and  was  quickly  covered  and  preserved 
from  decay.  And  still  the  building  went  on,  and  still  layer 
after  layer  was  placed,  till  many  fossils  lay  deep  down  beneath 
the  later-formed  layers ;  and  when  at  length,  by  slow  or  quick 
upheaval  of  the  ground,  this  sea-bottom  became  a  mountain, 
the  little  fossils  were  buried  within  the  body  of  that  mountain. 
So  wondrously  the  matter  appears  to  have  come  about. 

Another  difficulty  with  respect  to  the  stratified  rocks  has  to 
be  thought  of.  All  these  layers  or  deposits  of  gravel,  sand,  or 


GEOLOGY  241 

earth,  on  the  floor  of  the  ocean,  would  naturally  be  horizontal 
—that  is,  would  lie  flat,  one  upon  another.  In  places  the  ocean- 
floor  might  slant,  or  a  crevice  or  valley  or  ridge  might  break 
the  smoothness  of  the  deposit.  But  though  the  layers  might 
partake  of  the  slant,  though  the  valley  might  have  to  be  filled, 
though  the  ridge  might  have  to  be  surmounted,  still  the  general 
tendency  of  the  waves  would  be  to  level  the  dropping  deposits 
into  flat  layers. 

Then  how  is  it  that  when  we  examine  the  strata  of  rocks  in 
our  neighborhood,  wherever  that  neighborhood  may  be,  we  do 
not  find  them  so  arranged  ?  Here,  it  is  true,  the  lines  for  a 
space  are  nearly  horizontal,  but  there,  a  little  way  farther  on, 
they  are  perpendicular ;  here  they  are  bent,  and  there  curved ; 
here  they  are  slanting,  and  there  crushed  and  broken. 

This  only  bears  out  what  has  been  already  said  about  the 
Book  of  Geology.  It  has  been  bent  and  disturbed,  crushed 
and  broken. 

Great  powers  have  been  at  work  in  this  crust  of  our  earth. 
Continents  have  been  raised,  mountains  have  been  upheaved, 
vast  masses  of  rock  have  been  scattered  into  fragments.  Here 
or  there  we  may  find  the  layers  arranged  as  they  were  first  laid 
down,  but  far  more  often  we  discover  signs  of  later  disturbance, 
either  slow  or  sudden,  varying  from  a  mere  quiet  tilting  to  a 
violent  overturn. 

So  the  Book  of  Geology  is  a  torn  and  disorganized  volume, 
not  easy  to  read. 

Yet,  on  the  other  hand,  these  very  changes  which  have 
taken  place  are  a  help  to  the  geologist. 

It  may  seem  at  first  sight  as  if  we  should  have  an  easier 
task,  if  the  strata  were  all  left  lying  just  as  they  were  first 
formed,  in  smooth  level  layers,  one  above  another.  But  if  it 
were  so,  we  could  know  very  little  about  the  lower  layers. 

We  might  indeed  feel  sure,  as  we  do  now,  that  the  lowest 
layers  were  the  oldest  and  the  top  layers  the  newest,  and  that 
any  fossils  found  in  the  lower  layers  must  belong  to  an  age 
farther  back  than  any  fossils  found  in  the  upper  layers. 

So  much  would  be  clear.  And  we  might  dig  also  and  bur- 
row a  little  way  down,  through  a  few  different  kinds  of  rock, 
16 


242  ACHIEVEMENTS  IN  SCIENCE 

where  they  were  not  too  thick.     But  that  would  be  all.     There 
our  powers  would  cease. 

Now  how  different.  Through  the  heavings  and  tiltings  of 
the  earth's  crust,  the  lower  layers  are  often  pushed  quite  up  to 
the  surface,  so  that  we  are  able  to  examine  them  and  their  fos- 
sils without  the  least  difficulty,  and  very  often  without  digging 
underground  at  all. 

You  must  not  suppose  that  the  real  order  of  the  rocks  is 
changed  by  these  movements,  for  generally  speaking  it  is  not. 
The  lower  kinds  are  rarely,  if  ever,  found  placed  over  the  upper 
kinds;  only  the  ends  of  them  are  seen  peeping  out  above 
ground. 

It  is  as  if  you  had  a  pile  of  copy-books  lying  flat  one  upon 
another,  and  were  to  put  your  finger  under  the  lowest  and  pusl 
it  up.  All  those  above  would  be  pushed  up  also,  and  perhaps 
they  would  slip  a  little  way  down,  so  that  you  would  have  a 
row  of  edges  showing  side  by  side,  at  very  much  the  same 
height.  The  arrangement  of  the  copy-books  would  not  be 
changed,  for  the  lowest  would  still  be  the  lowest  in  actual  posi- 
tion ;  but  a  general  tilting  or  upheaval  would  have  taken  place. 

Just  such  a  tilting  or  upheaval  has  taken  place  again  anc 
again  with  the  rocks  forming  our  earth-crust.  The  edges 
the  lower  rocks  often  show  side  by  side  with  those  of  higher 
layers. 

But  geologists  know  them  apart.  They  are  able  to  tell  con- 
fidently whether  such  and  such  a  rock,  peeping  out  at  th< 
earth's  surface,  belongs  really  to  a  lower  or  a  higher  kind.  For 
there  is  a  certain  sort  of  order  followed  in  the  arrangement  of 
rock-layers  all  over  the  earth,  and  it  is  well  known  that  some 
rocks  are  never  found  below  some  other  rocks,  that  certain  par- 
ticular kinds  are  never  placed  above  certain  other  kinds.  Thus 
it  follows  that  the  fossils  found  in  one  description  of  rock  must 
be  the  fossils  of  animals  which  lived  and  died  before  the  ani- 
mals whose  fossil  remains  are  found  in  another  neighboring 
rock,  just  because  this  last  rock-layer  was  built  upon  the  ocean- 
floor  above  and  therefore  later  than  the  other. 

All  this  is  part  of  the  foreign  language  of  geology — part  of 
the  piecing  and  arranging  of  the  torn  volume.  Many  mistakes 


GEOLOGY  243 

are  made ;  many  blunders  are  possible ;  but  the  mistakes  and 
blunders  are  being  gradually  corrected,  and  certain  rules  by 
which  to  read  and  understand  are  becoming  more  and  more 
clear. 

It  has  been  already  said  that  unstratified  rocks  are  those 
which  have  been  at  some  period,  whether  lately  or  very  long 
ago,  in  a  liquid  state  from  intense  heat,  and  which  have  since 
cooled,  either  quickly  or  slowly,  crystallizing  as  they  cooled. 

Unstratified  rocks  may  be  divided  into  two  distinct  classes. 

First. — Volcanic  rocks,  such  as  lava.  These  have  been 
quickly  cooled  at  the  surface  of  the  earth,  or  not  far  below  it. 

Secondly. — Plutonic  rocks,  such  as  granite.  These  have 
been  slowly  cooled  deep  down  in  the  earth  under  heavy  pressure. 

There  is  also  a  class  of  rocks,  called  metamorphic  rocks,  in- 
cluding some  kinds  of  marble.  These  are,  strictly  speaking, 
crystalline  rocks,  and  yet  they  are  arranged  in  something  like 
layers.  The  word  "metamorphic"  simply  means  "trans- 
formed." They  are  believed  to  have  been  once  stratified  rocks, 
perhaps  containing  often  the  remains  of  animals ;  but  intense 
heat  has  later  transformed  them  into  crystalline  rocks,  and  the 
animal  remains  have  almost  or  quite  vanished. 

Just  as  the  different  kinds  of  stratified  rocks  are  often 
called  aqueous  rocks,  or  rocks  formed  by  the  action  of  water 
— so  these  different  kinds  of  unstratified  rocks  are  often 
called  igneous  rocks,  or  rocks  formed  by  the  action  of  fire — 
the  name  being  taken  from  the  Latin  word  for  fire.  The  meta- 
morphic rocks  are  sometimes  described  as  "  Aqueo-igneous," 
since  both  water  and  fire  helped  in  the  forming  of  them. 

It  was  at  one  time  believed,  as  a  matter  of  certainty,  that 
granite  and  such  rocks  belonged  to  a  period  much  farther  back 
than  the  periods  of  the  stratified  rocks.  That  is  to  say,  it  was 
supposed  that  fire-action  had  come  first  and  water-action  sec- 
ond ;  that  the  fire-made  rocks  were  all  formed  in  very  early 
ages,  and  that  only  water-made  rocks  still  continued  to  be 
formed.  So  the  name  of  Primary  Rocks,  or  First  Rocks,  was 
given  to  the  granites  and  other  such  rocks,  and  the  name  of 
Secondary  Rocks  to  all  water-built  rocks,  while  those  of  the 
third  class  were  called  Transition  Rocks,  because  they  seemed 


244  ACHIEVEMENTS  IN  SCIENCE 

to  be  a  kind  of  link  or  stepping-stone  in  the  change  from  the 
First  to  the  Second  Rocks. 

The  chief  reason  for  the  general  belief  that  fire-built  rocks 
were  older  than  water-built  ones  was,  that  the  former  are  as  a 
rule  found  to  lie  lower  than  the  latter.  They  form,  as  it  were, 
the  basement  of  the  building,  while  the  top-stories  are  made  of 
water-built  rocks. 

Many  still  believe  that  there  is  much  truth  in  the  thought. 
It  is  most  probable,  so  far  as  we  are  able  to  judge,  that  t 
formed  crust  of  rocks  all  over  the  earth  was  of  cooled  and  cryj 
tallized  material.     As  these  rocks  were  crumbled  and  waste 
by  the  ocean,  materials  would  have  been  supplied  for  the  build- 
ing-up of  rocks,  layer  upon  layer. 

But  this  is  conjecture.    We  cannot  know  with  any  cer taint; 
the  course  of  events  so  far  back  in  the  past.    And  geologist j 
are  now  able  to  state  with  tolerable  confidence  that,  however 
old  many  of  the  granites  may  be,  yet  a  large  amount  of  t 
fire-built  rocks  are  no  older  than  the  water-built  rocks  which 
over  them. 

So  by  many  geologists  the  names  of  Primary,  Transition, 
Secondary  Formations  are  pretty  well  given  up.     It  has 
proposed  to  give  instead  to  the  crystallized  rocks  of  all  kind* 
the  name  of  Underlying  Rocks  (Hypogene  Rocks). 

But  if  they  really  do  lie  under,  how  can  they  possibly  be 
the  same  age?     One  would  scarcely  venture  to  suppose, 
looking  at  a  building,  that  the  cellars  had  not  been  finished 
fore  the  upper  floors. 

True.     In  the  first  instance  doubtless  the  cellars  were  fin 
made,  then  the  ground-floor,  then  the  upper  stories. 

When,  however,  the  house  was  so  built,  alterations  and  ii 
provements  might  be  very  widely  carried  on  above  and  below. 
While  one  set  of  workmen  were  engaged  in  remodeling  the 
roof,  another  set  of  workmen  might  be  engaged  in  remodeling 
the  kitchens  and  first  floor,  pulling  down,  propping  up,  and 
actually  rebuilding  parts  of  the  lower  walls. 

This  is  precisely  what  the  two  great  fellow-workmen,  Fire 
and  Water,  are  ever  doing  in  the  crust  of  our  earth.  And  if  it 
be  objected  that  such  alterations  too  widely  undertaken  might 


GEOLOGY  245 

result  in  slips,  cracks,  and  slidings,  of  ceilings  and  walls  in  the 
upper  stories,  I  can  only  say  that  such  catastrophes  have  been 
the  result  of  underground  alterations  in  that  great  building,  the 
earth's  crust.  .  .  . 

We  see  therefore  clearly  that,  although  the  earliest  fire- 
made  rocks  may  very  likely  date  farther  back  than  the  earliest 
water-made  rocks,  yet  the  making  of  the  two  kinds  has  gone 
on  side  by  side,  one  below  and  the  other  above  ground,  through 
all  ages  up  to  the  present  moment. 

And  just  as  in  the  present  day  water  continues  its  busy 
work  above  ground  of  pulling  down  and  building  up,  so  also 
fire  continues  its  busy  work  underground  of  melting  rocks 
which  afterward  cool  into  new  forms,  and  also  of  shattering 
and  upheaving  parts  of  the  earth-crust. 

For  there  can  be  no  doubt  that  fiery  heat  does  exist  as  a 
mighty  power  within  our  earth,  though  to  what  extent  we  are 
not  able  to  say. 

These  two  fellow-workers  in  nature  have  different  modes  of 
working.  One  we  can  see  on  all  sides,  quietly  progressing,  de- 
molishing land  patiently  bit  by  bit,  building  up  land  steadily 
grain  by  grain.  The  other,  though  more  commonly  hidden 
from  sight,  is  fierce  and  tumultuous  in  character,  and  shows  his 
power  in  occasional  terrific  outbursts. 

We  can  scarcely  realize  what  the  power  is  of  the  imprisoned 
fiery  forces  underground,  though  even  we  are  not  without  some 
witness  of  their  existence.  From  time  to  time  even  our  firm 
land  has  been  felt  to  tremble  with  a  thrill  from  some  far-off 
shock;  and  even  in  our  country  is  seen  the  marvel  of  scalding 
water  pouring  unceasingly  from  deep  underground  .... 

Think  of  the  tremendous  eruptions  of  Vesuvius,  of  Etna,  of 
Hecla,  of  Mauna  Loa.  Think  of  whole  towns  crushed  and 
buried,  with  their  thousands  of  living  inhabitants.  Think  of 
rivers  of  glowing  lava  streaming  up  from  regions  below  ground, 
and  pouring  along  the  surface  for  a  distance  of  forty,  fifty,  and 
even  sixty  miles,  as  in  Iceland  and  Hawaii.  Think  of  red-hot 
cinders  flung  from  a  volcano-crater  to  a  height  of  10,000  feet. 
Think  of  lakes  of  liquid  fire  in  other  craters,  five  hundred  to  a 


246  ACHIEVEMENTS  IN  SCIENCE 

thousand  feet  across,  huge  caldrons  of  boiling  rock.  Think 
of  showers  of  ashes  from  the  furnace  below  of  yet  another, 
borne  so  high  aloft  as  to  be  carried  seven  hundred  miles  before 
they  sank  to  earth  again.  Think  of  millions  of  red-hot  stones 
flung  out  in  one  eruption  of  Vesuvius.  Think  of  a  mass  of 
rock,  one  hundred  cubic  yards  in  size,  hurled  to  a  distance  of 
eight  miles  or  more  out  of  the  crater  of  Cotopaxi. 

Think  also  of  earthquake-shocks  felt  through  1,200  miles  of 
country.  Think  of  fierce  tremblings  and  heavings  lasting  ii 
constant  succession  through  days  and  weeks  of  terror.  Think 
of  hundreds  of  miles  of  land  raised  several  feet  in  one  great  up- 
heaval. Think  of  the  earth  opening  in  scores  of  wide-lipped 
cracks,  to  swallow  men  and  beasts.  Think  of  hot  mud,  boiling 
water,  scalding  steam,  liquid  rock,  bursting  from  such  cracks, 
or  pouring  from  rents  in  a  mountain-side. 

Truly  these  are  signs  of  a  state  of  things  in  or  below  the 
solid  crust  on  which  we  live,  that  may  make  us  doubt  the  abso- 
lute security  of  "  Mother  Earth." 

Different  explanations  have  been  put  forward  to  explain  this 
seemingly  fiery  state  of  things  underground. 

Until  lately  the  belief  was  widely  "held  that  our  earth  was 
one  huge  globe  of  liquid  fire,  with  only  a  slender  cooled  crust 
covering  her,  a  few  miles  in  thickness. 

This  view  was  supported  by  the  fact  that  heat  is  found  to 
increase  as  men  descend  into  the  earth.  Measurements  of 
such  heat-increase  have  been  taken,  both  in  mines  and  in  bor- 
ings for  wells.  The  usual  rate  is  about  one  degree  more  of 
heat,  of  our  common  thermometer,  for  every  fifty  or  sixty  feet 
of  descent.  If  this  were  steadily  continued,  water  would  boil 
at  a  depth  of  8,000  feet  below  the  surface ;  iron  would  melt  at 
a  depth  of  twenty-eight  miles;  while  at  a  depth  of  forty  or 
fifty  miles  no  known  substance  upon  earth  could  remain 
solid. 

The  force  of  this  proof  is,  however,  weakened  by  the  fact 
that  the  rate  at  which  the  heat  increases  differs  very  much  in 
different  places.  Also  it  is  now  generally  supposed  that  such 
a  tremendous  furnace  of  heat — a  furnace  nearly  8,000  miles  in 


GEOLOGY  247 

diameter — could  not  fail  to  break  up  and  melt  so  slight  a  cover- 
ing shell. 

Many  believe,  therefore,  not  that  the  whole  interior  of  the 
earth  is  liquid  with  heat,  but  that  enormous  fire-seas  or  lakes 
of  melted  rock  exist  here  and  there,  under  or  in  the  earth-crust. 
From  these  lakes  the  volcanoes  would  be  fed,  and  they  would 
be  the  cause  of  earthquakes  and  land-upheavals  or  land-sinking. 
There  are  strong  reasons  for  supposing  that  the  earth  was  once 
a  fiery  liquid  body,  and  that  she  has  slowly  cooled  through  long 
ages.  Some  hold  that  her  center  probably  grew  solid  first  from 
tremendous  pressure ;  that  her  crust  afterward  became  gradu- 
ally cold ;  and  that  between  the  solid  crust  and  the  solid  inside 
or  "nucleus,"  a  sea  of  melted  rock  long  existed,  the  remains  of 
which  are  still  to  be  found  in  these  tremendous  fiery  reservoirs. 

The  idea  accords  well  with  the  fact  that  large  numbers  of 
extinct  or  dead  volcanoes  are  scattered  through  many  parts  of 
the  earth.  If  the  above  explanation  be  the  right  one,  doubtless 
the  fire-seas  in  the  crust  extended  once  upon  a  time  beneath 
such  volcanoes,  but  have  since  died  out  or  smoldered  low  in 
those  parts. 

A  somewhat  curious  calculation  has  been  made,  to  illus- 
trate the  different  modes  of  working  of  these  two  mighty 
powers — Fire  and  Water. 

The  amount  of  land  swept  away  each  year  in  mud,  and  borne 
to  the  ocean  by  the  River  Ganges,  was  roughly  reckoned,  and 
also  the  amount  of  land  believed  to  have  been  upheaved  several 
feet  in  the  great  Chilian  earthquake. 

It  was  found  that  the  river,  steadily  working  month  by 
month,  would  require  some  four  hundred  years  to  carry  to  the 
sea  the  same  weight  of  material,  which  in  one  tremendous 
effort  was  upheaved  by  the  fiery  underground  forces. 

Yet  we  must  not  carry  this  distinction  too  far.  Fire  does 
not  always  work  suddenly,  or  water  slowly;  witness  the  slow 
rising  and  sinking  of  land  in  parts  of  the  earth,  continuing 
through  centuries ;  and  witness  also  the  effects  of  great  floods 
and  storms. 

The  crust  of  the  earth  is  made  of  rock,  But  what  is  rock 
made  of  ? 


248  ACHIEVEMENTS  IN  SCIENCE 

Certain  leading  divisions  of  rocks  have  been  already  con- 
sidered : 

The  Water-made  Rocks; 

The  Fire-made  Rocks,  both  Plutonic  and  Volcanic ; 

The  Water-and-Fire-made  Rocks. 

The  first  of  these — Water-made  Rocks — may  be  subdivided 
into  three  classes.    These  are, — 
I.     Flint  Rocks; 
II.     Clay  Rocks; 

III.     Lime  Rocks. 

This  is  not  a  book  in  which  it  would  be  wise  to  go  closely 
into  the  mineral  nature  of  rocks.  Two  or  three  leading 
thoughts  may,  however,  be  given. 

Does  it  not  seem  strange  that  the  hard  and  solid  rocks 
should  be  in  great  measure  formed  of  the  same  substances 
which  form  the  thin  invisible  air  floating  around  us  ? 

Yet  so  it  is.  There  is  a  certain  gas  called  oxygen  gas. 
Without  that  gas  you  could  not  live  many  minutes.  Banish  it 
from  the  room  in  which  you  are  sitting,  and  in  a  few  minutes 
you  will  die. 

This  gas  makes  up  nearly  one-quarter  by  weight  of  the  at- 
mosphere round  the  whole  earth. 

The  same  gas  plays  an  important  part  in  the  ocean ;  for 
more  than  three-quarters  of  water  is  oxygen. 

It  plays  also  an  important  part  in  rocks ;  for  about  half  the 
material  of  the  entire  earth's  crust  is  oxygen. 

Another  chief  material  in  rocks  is  silicon.  This  makes  up 
one-quarter  of  the  crust,  leaving  only  one-quarter  to  be  ac- 
counted for.  Silicon  mixed  with  oxygen  makes  silica  or  quartz. 
There  are  few  rocks  which  have  not  a  large  amount  of  quartz 
in  them.  Common  flint,  sandstones,  and  the  sand  of  our 
shores  are  made  of  quartz,  and  therefore  belong  to  the  first 
class  of  silicious  or  flint  rocks.  Granites  and  lavas  are  about 
one-half  quartz.  The  beautiful  stones,  amethyst,  agate,  chal- 
cedony, and  jasper,  are  all  different  kinds  of  quartz. 

Another  chief  material  in  rocks  is  a  white  metal  called  alu- 
minium. United  to  oxygen  it  becomes  alumina,  the  chief  sub- 
stance in  clay.  Rocks  of  this  kind — such  as  clays,  and  also 


GEOLOGY  249 

the  lovely  blue  gem,  sapphire — are  called  argillaceous  rocks, 
from  the  Latin  word  for  clay,  and  belong  to  the  second  class. 
Such  rocks  keep  fossils  well. 

Another  is  calcium.  United  to  oxygen  and  carbonic  acid, 
it  makes  carbonate  of  lime,  the  chief  substance  in  limestone ; 
so  all  limestones  belong  to  the  third  class  of  calcareous  or 
lime  rocks. 

Other  important  materials  may  be  mentioned,  such  as  mag- 
nesium, potassium,  sodium,  iron,  carbon,  sulphur,  hydrogen, 
chlorine,  nitrogen.  These,  with  many  more,  not  so  common, 
make  up  the  remaining  quarter  of  the  earth-crust. 

Carbon  plays  as  important  a  part  in  animal  and  vegetable 
life  as  silicon  in  rocks.  Carbon  is  most  commonly  seen  in 
three  distinct  forms — as  charcoal,  as  black-lead,  and  as  the  pure 
brilliant  diamond.  Carbon  united,  in  a  particular  proportion, 
to  oxygen,  forms  carbonic  acid ;  and  carbonic  acid  united,  in  a 
particular  proportion,  to  lime,  forms  limestone. 

Hydrogen  united  to  oxygen  forms  water.  Each  of  these 
two  gases  is  invisible  alone,  but  when  they  meet  and  mingle 
they  form  a  liquid. 

Nitrogen  united  to  oxygen  and  to  a  small  quantity  of  car- 
bonic acid  gas  forms  our  atmosphere. 

Rocks  of  pure  flint,  pure  clay,  or  pure  lime  are  rarely  or 
never  met  with.  Most  rocks  are  made  up  of  several  different 
substances  melted  together. 

In  the  fire-built  rocks  no  remains  of  animals  are  found, 
though  in  water-built  rocks  they  abound.  Water-built  rocks 
are  sometimes  divided  into  two  classes — those  which  only  con- 
tain occasional  animal  remains,  and  those  which  are  more  or 
less  built  up  of  the  skeletons  of  animals. 

There  are  some  exceedingly  tiny  creatures  inhabiting  the 
ocean,  called  Rhizopods.  They  live  in  minute  shells,  the 
largest  of  which  may  be  almost  the  size  of  a  grain  of  wheat, 
but  by  far  the  greater  number  are  invisible  as  shells  without  a 
microscope,  and  merely  show  as  fine  dust.  The  rhizopods  are 
of  different  shapes,  sometimes  round,  sometimes  spiral,  some- 
times having  only  one  cell,  sometimes  having  several  cells.  In 


250 


ACHIEVEMENTS  IN  SCIENCE 


the  latter  case  a  separate  animal  lives  in  each  cell.  The  ani- 
mal is  of  the  very  simplest  as  well  as  the  smallest  kind.  He 
has  not  even  a  mouth  or  a  stomach,  but  can  take  in  food  at  any 
part  of  his  body. 

These  rhizopods  live  in  the  oceans  in  enormous  numbers. 
Tens  of  millions  are  ever  coming  into  existence,  living  out  their 
tiny  lives,  dying,  and  sinking  to  the  bottom.  There  upon  the 
ocean-floor  gather  their  remains,  a  heaped-up  multitude  of  min- 
ute skeletons  or  shells,  layer  forming  over  layer. 

It  was  long  suspected  that  the  white  chalk  cliffs  of  England 
were  built  up  in  some  such  manner  as  this  through  past  ages. 
And  now  at  length  proof  has  been  found,  in  the  shape  of  mud 
dredged  up  from  the  ocean-bottom — mud  entirely  composed 
of  countless  multitudes  of  these  little  shells,  dropping  there 
by  myriads,  and  becoming  slowly  joined  together  in  one 
mass. 

Just  so,  it  is  believed,  were  the  white  chalk  cliffs  built — 
gradually  prepared  on  the  ocean-floor,  and  then  slowly  or  sud- 
denly upheaved,  so  as  to  become  a  part  of  the  dry  land. 

Think  what  the  enormous  numbers  must  have  been  of  tiny 
living  creatures,  out  of  whose  shells  the  wide  reaches  of  white 
chalk  cliffs  have  been  made.  Chalk  cliffs  and  chalk  layers  ex- 
tend from  Ireland,  through  England  and  France,  as  far  as  to 
the  Crimea.  In  the  south  of  Russia  they  are  said  to  be  six 
hundred  feet  thick.  Yet  one  cubic  inch  of  chalk  is  calculated 
to  hold  the  remains  of  more  than  one  million  rhizopods.  How 
many  countless  millions  upon  millions  must  have  gone  to  the 
whole  structure!  How  long  must  the  work  of  building  up 
have  lasted ! 

These  little  shells  do  not  always  drop  softly  and  evenly  to 
the  ocean-floor,  to  become  quietly  part  of  a  mass  of  shells. 
Sometimes,  where  the  ocean  is  shallow  enough  for  the  waves  to 
have  power  below,  or  where  land  currents  can  reach,  they  are 
washed  about,  and  thrown  one  against  another,  and  ground 
into  fine  powder ;  and  the  fine  powder  becomes  in  time,  through 
different  causes,  solid  rock. 

Limestone  is  made  in  another  way  also.  In  the  warm 
waters  of  the  South  Pacific  Ocean  there  are  many  islands, 


GEOLOGY  251 

large  and  small,  which  have  been  formed  in  a  wonderful  man- 
ner by  tiny  living  workers.  The  workers  are  soft  jelly-like 
creatures,  called  polyps,  who  labor  together  in  building  up 
great  walls  and  masses  of  coral. 

They  never  carry  on  their  work  above  the  surface  of  the 
water,  for  in  the  air  they  would  die.  But  the  waves  break  the 
coral,  and  heap  it  up  above  high-water  mark,  and  carry  earth 
and  seeds  to  drop  there  till  at  length  a  small  low-lying  island  is 
formed. 

The  waves  not  only  heap  up  broken  coral,  but  they  grind 
the  coral  into  fine  powder,  and  from  this  powder  limestone 
rock  is  made,  just  as  it  is  from  the  powdered  shells  of  rhizo- 
pods.  The  material  used  by  the  polyps  in  building  the  coral  is 
chiefly  lime,  which  they  have  the  power  of  gathering  out  of 
the  water,  and  the  fine  coral-powder,  sinking  to  the  bottom, 
makes  large  quantities  of  hard  limestone.  Soft  chalk  is  rarely, 
if  ever,  found  near  the  coral  islands. 

Limestones  are  formed  in  the  same  manner  from  the  grind- 
ing up  of  other  sea-shells  and  fossils,  various  in  kind ;  the  pow- 
der becoming  gradually  united  into  solid  rock. 

There  is  yet  another  way  in  which  limestone  is  made,  quite 
different  from  all  these.  Sometimes  streams  of  water  have  a 
large  quantity  of  lime  in  them ;  and  these  as  they  flow  will  drop 
layers  of  lime  which  harden  into  rock.  Or  a  lime-laden  spring, 
making  its  way  through  the  roof  of  an  underground  cavern, 
will  leave  all  kinds  of  fantastic  arrangements  of  limestone 
wherever  its  waters  can  trickle  and  drip.  Such  a  cavern  is 
called  a  "  stalactite  cave." 

So  there  are  different  kinds  of  fossil  rock-making.  There 
may  be  rocks  made  of  other  materials,  with  fossil  simply  buried 
in  them.  There  may  be  rocks  made  entirely  of  fossils,  which 
have  gathered  in  masses  as  they  sank  to  the  sea-bottom,  and 
have  there  become  simply  and  lightly  joined  together.  There 
may  be  rocks  made  of  the  ground-up  powder  of  fossils,  pressed 
into  a  solid  substance  or  united  by  some  other  substance. 

Rocks  are  also  often  formed  of  whole  fossils,  or  stones,  or 

lells,  bound  into  one  by  some  natural  soft  sticky  cement, 


252  ACHIEVEMENTS  IN  SCIENCE 

which  has  gathered  round  them  and  afterward  grown  hard, 
like  the  cement  which  holds  together  the  stones  in  a  wall. 

The  tiny  rhizopods  (meaning  root  foot),  which  have  so  large 
a  share  in  chalk  and  limestone  making,  are  among  the  smallest 
and  simplest  known  kinds  of  animal  life. 

There  are  also  some  very  minute  forms  of  vegetable  life, 
which  exist  in  equally  vast  numbers,  called  diatoms.  For  a 
long  while  they  were  believed  to  be  living  animals,  like  the 
rhizopods.  Scientific  men  are  now,  however,  pretty  well  agreed 
that  they  really  are  only  vegetables  or  plants. 

The  diatoms  have  each  one  a  tiny  shell  or  shield,  not  made 
of  lime  like  the  rhizopod-shells,  but  of  flint.  Some  think  that 
common  flint  may  be  formed  of  these  tiny  shells. 

Again,  there  is  a  kind  of  rock  called  mountain  meal,  which 
is  entirely  made  up  of  the  remains  of  diatoms.  Examined 
under  the  microscope,  thousands  of  minute  flint  shields  of  vari- 
ous shapes  are  seen.  This  rock,  or  earth,  is  very  abundant  in 
many  places,  and  is  sometimes  used  as  a  polishing  powder.  In 
Bohemia  there  is  a  layer  of  it  no  less  than  fourteen  feet  thick. 
Yet  so  minute  are  the  shells  of  which  it  is  composed,  that  one 
square  inch  of  rock  is  said  to  contain  about  four  thousand  mil- 
lions of  them.  Each  one  of  these  millions  is  a  separate  distinct 
fossil  .... 

If  you  examine  carefully  a  piece  of  coal,  you  will  find,  more 
or  less  clearly,  markings  like  those  which  are  seen  in  a  piece  of 
wood.  Sometimes  they  are  very  distinct  indeed.  Coal  abounds 
in  impressions  of  leaves,  ferns,  and  stems,  and  fossil  remains  of 
plants  and  tree-trunks  are  found  in  numbers  in  coal-seams. 

Coal  is  a  vegetable  substance.  The  wide  coal-fields  of 
Britain  and  other  lands  are  fat  fossil  remains  of  vast  forests. 

Long  ages  ago,  as  it  seems,  broad  and  luxuriant  forests 
flourished  over  the  earth.  In  many  parts  generation  after 
generation  of  trees  lived  and  died  and  decayed,  leaving  no  trace 
of  their  existence,  beyond  a  little  layer  of  black  mold,  soon  to 
be  carried  away  by  wind  and  water.  Coal  could  only  be  formed 
where  there  were  bogs  and  quagmires. 

But  in  bogs  and  quagmires,  and  in  shallow  lakes  of  low- 


GEOLOGY  253 

lying  lands,  there  were  great  gatherings  of  slowly  decaying 
vegetable  remains,  trees,  plants,  and  ferns  all  mingling  together. 
Then  after  a  while  the  low  lands  would  sink  and  the  ocean 
pouring  in  would  cover  them  with  layers  of  protecting  sand  or 
mud ;  and  sometimes  the  land  would  rise  again,  and  fresh  for- 
ests would  spring  into  life,  only  to  be  in  their  turn  overwhelmed 
anew,  and  covered  by  fresh  sandy  or  earthy  deposits. 

These  buried  forests  lay  through  the  ages  following,  slowly 
hardening  into  the  black  and  shining  coal,  so  useful  now  to 
man. 

The  coal  is  found  thus  in  thin  or  thick  seams,  with  other 
rock-layers  between,  telling  each  its  history  of  centuries  long 
past.  In  one  place  no  less  than  sixteen  such  beds  of  coal  are 
found,  one  below  another,  each  divided  from  the  next  above  and 
the  next  underneath  by  beds  of  clay  or  sand  or  shale.  The 
forests  could  not  have  grown  in  the  sea,  and  the  earth-layers 
could  not  have  been  formed  on  land,  therefore  many  land-ris- 
ings and  sinkings  must  have  taken  place.  Each  bed  probably 
tells  the  tale  of  a  succession  of  forests 

Before  going  on  to  a  sketch  of  the  early  ages  of  the  Earth's 
history — ages  stretching  back  long  long  before  the  time  of 
Adam — it  is  needful  to  think  yet  for  a  little  longer  about  the 
manner  in  which  that  history  is  written,  and  the  way  in  which 
it  has  to  be  read. 

For  the  record  is  one  difficult  to  make  out,  and  its  style  of 
expression  is  often  dark  and  mysterious.  There  is  scarcely 
any  other  volume  in  the  great  Book  of  Nature  which  the  stu- 
dent is  so  likely  to  misread  as  this  one.  It  is  very  needful, 
therefore,  to  hold  the  conclusions  of  geologists  with  a  light 
grasp,  guarding  each  with  a  "  perhaps  "  or  a  "  may  be."  Many 
an  imposing  edifice  has  been  built,  in  geology,  upon  a  rickety 
foundation  which  has  speedily  given  way. 

In  all  ages  of  the  world's  history  up  to  the  present  day, 
rock-making  has  taken  place — fire-made  rocks  being  fashioned 
underground,  and  water-made  rocks  being  fashioned  above 
ground  though  under  water. 

Also  in  all  ages  different  kinds  of  rocks  have  been  fashioned 


J54 


ACHIEVEMENTS  IN  SCIENCE 


side  by  side— limestone  in  one  part  of  the  world,  sandstone  in 
another,  chalk  in  another,  clay  in  another,  and  so  on.  There 
have,  it  is  true,  been  ages  when  one  kind  seems  to  have  been 
the  chief  kind — an  age  of  limestone,  or  an  age  of  chalk.  But 
even  then  there  were  doubtless  more  rock-buildings  going  on, 
though  not  to  so  great  an  extent.  On  the  other  hand,  there 
may  have  been  ages  during  which  no  limestone  was  made,  or 
no  chalk,  or  no  clay.  As  a  general  rule,  however,  the  various 
sorts  of  rock-building  have  probably  gone  on  together.  This 
was  not  so  well  understood  by  early  geologists  as  it  is  now. 

The  difficulty  is  often  great  of  disentangling  the  different 
strata,  and  saying  which  was  earlier  and  which  later  formed. 

Still,  by  close  and  careful  study  of  the  rocks  which  compose 
the  earth's  crust,  a  certain  kind  of  order  is  found  to  exist,  more 
or  less  followed  out  in  all  parts  of  the  world.  When  each  layer 
was  formed  in  England  or  in  America,  the  geologist  cannot 
possibly  say.  He  can,  however,  assert,  in  either  place,  that  a 
certain  mass  of  rock  was  formed  before  a  certain  other  mass  in 
that  same  place,  even  though  the  two  may  seem  to  lie  side  by 
side ;  for  he  knows  that  they  were  so  placed  only  by  upheaval, 
and  that  once  upon  a  time  the  one  lay  beneath  the  other. 

The  geologist  can  go  further.  He  can  often  declare  that  a 
certain  mass  of  rock  in  America  and  a  certain  mass  of  rock  in 
England,  quite  different  in  kind,  were  probably  built  up  at 
about  the  same  time.  How  long  ago  that  time  was  he  would 
be  rash  to  attempt  to  say ;  but  that  the  two  belong  to  the  same 
age  he  has  good  reason  for  supposing. 

We  find  rocks  piled  upon  rocks  in  a  certain  order,  so  that 
we  may  generally  be  pretty  confident  that  the  lower  rocks  were 
first  made,  and  the  upper  rocks  the  latest  built.  Further  than 
this,  we  find  in  all  the  said  layers  of  water-built  rocks  signs  of 
past  life. 

As  already  stated,  much  of  this  life  was  ocean-life,  though 
not  all. 

Below  the  sea,  as  the  rock-layers  were  being  formed,  bit  by 
bit,  of  earth  dropping  from  the  ocean  to  the  ocean's  floor,  sea- 
creatures  lived  out  their  lives  and  died  by  thousands,  to  sink  to 
that  same  floor.  Millions  passed  away,  dissolving  and  leaving 


GEOLOGY  255 

no  trace  behind ;  but  thousands  were  preserved — shells  often, 
animals  sometimes. 

Nor  was  this  all.  For  now  and  again  some  part  of  the  sea- 
bottom  was  upheaved,  slowly  or  quickly,  till  it  became  dry  land. 
On  this  dry  land  animals  lived  again,  and  thousands  of  them, 
too,  died,  and  their  bones  crumbled  into  dust.  But  here  and 
there  one  was  caught  in  bog  or  frost,  and  his  remains  were  pre- 
served till,  through  lapse  of  ages,  they  turned  to  stone. 

Yet  again  that  land  would  sink,  and  over  it  fresh  layers 
were  formed  by  the  ocean-waters,  with  fresh  remains  of  sea- 
animals  buried  in  with  the  layers  of  sand  or  lime ;  and  once 
more  the  sea-bottom  would  rise,  perhaps  then  to  continue  as 
dry  land,  until  the  day  when  man  should  discover  and  handle 
these  hidden  remains. 

Now  note  a  remarkable  fact  as  to  these  fossils,  scattered  far 
and  wide  through  the  layers  of  stratified  rock.  In  the  upper- 
most and  latest-built  rocks  the  animals  found  are  the  same,  in 
great  measure,  as  those  which  now  exist  upon  the  earth. 

Leaving  the  uppermost  rocks,  and  examining  those  which 
lie  a  little  way  below  we  find  a  difference.  Some  are  still  the 
same,  and  others,  if  not  quite  the  same,  are  very  much  like 
what  we  have  now ;  but  here  and  there  a  creature  of  a  different 
form  appears. 

Go  deeper  still,  and  the  kinds  of  animals  change  further. 
Fewer  and  fewer  resemble  those  which  now  range  the  earth ; 
more  and  more  belong  to  other  species. 

Descend  through  layer  after  layer  till  we  come  to  rocks 
built  in  earliest  ages,  and  not  one  fossil  shall  we  find  precisely 
the  same  as  one  animal  living  now. 

So  not  only  are  the  rocks  built  in  successive  order,  stratum 
after  stratum  belonging  to  age  after  age  in  the  past,  but  fossil- 
remains  also  are  found  in  successive  order,  kind  after  kind  be- 
longing to  past  age  after  age. 

Although  in  the  first  instance  the  succession  of  fossils  was 
understood  by  means  of  the  succession  of  rock-layers,  yet  in 
the  second  place  the  arrangement  of  rock-layers  is  made  more 
clear  by  the  means  of  these  very  fossils. 

A  geologist,  looking  at  the  rocks  in  America,  can  say  which 


256 


ACHIEVEMENTS  IN  SCIENCE 


there  were  first-formed,  which  second-formed,  which  third- 
formed.  Also,  looking  at  the  rocks  in  England,  he  can  say 
which  there  were  first-formed,  second-formed,  third-formed. 
He  would,  however,  find  it  very  difficult,  if  not  impossible,  to 
say  which  among  any  of  the  American  rocks  was  formed  at 
about  the  same  time  as  any  particular  one  among  the  English 
rocks,  were  it  not  for  the  help  afforded  him  by  these  fossils. 

Just  as  the  regular  succession  of  rock-strata  has  been  gradi 
ally  learned,  so  the  regular  succession  of  different  fossils  is  b< 
coming  more  and  more  understood.     It  is  now  known  that 
some  kinds  of  fossils  are  always  found  in  the  oldest  rocks,  and 
in  them  only ;  that  some  kinds  are  always  found  in  the  newest 
rocks,  and  in  them  only ;  that  some  fossils  are  rarely  or  never 
found  lower  than  certain  layers ;  that  some  fossils  are  rarely 
or  never  found  higher  than  certain  other  layers. 

So  this  fossil  arrangement  is  growing  into  quite  a  history 
the  past.     And  a  geologist,  looking  at  certain  rocks,  pushed 
from    underground,  in   England  and   in  America,  can    say; 
"  These  are  very  different  kinds  of  rocks,  it  is  true,  and  it  woul 
be  impossible  to  say  how  long  the  building  up  of  the  one  mighl 
have  taken  place  before  or  after  the  other.     But  I  see  that 
both  these  rocks  there  are  exactly  the  same  kinds  of  fossil 
remains,  differing  from  those  in  the  rocks  above  and  below, 
conclude  therefore  that  the  two  rocks  belong  to  about  the  sai 
great  age  in  the  world's  past  history,  when  the  same  anii 
were  living  upon  the  earth." 

Observing  and  reasoning  thus,  geologists  have  drawn  up 
general  plan  or  order  of  strata;  and  the  whole  of  the  vast 
masses  of  water-built  rocks  throughout  the  world  have 
arranged  in  a  regular  succession  of  classes,  rising  step  by  st 
from  earliest  ages  up  to  the  present  time. 


PHYSICAL  GEOGRAPHY 


The  Atmosphere 

By  ELISHA  GRAY 

IV  TETEOROLOGY  is  a  science  that  at  one  time  included 
1VJL  astronomy,  but  now  it  is  restricted  to  the  weather,  sea- 
sons, and  all  phenomena  that  are  manifested  in  the  atmosphere 
in  its  relation  to  heat,  electricity,  and  moisture,  as  well  as  the 
laws  that  govern  the  ever-varying  conditions  of  the  circumam- 
bient air  of  our  globe.  The  air  is  made  up  chiefly  of  oxygen 
and  nitrogen,  in  the  proportions  of  about  twenty-one  parts  of 
oxygen  and  seventy-nine  parts  nitrogen  by  volume,  and  by 
weight  about  twenty-three  parts  of  oxygen  and  seventy-seven  of 
nitrogen.  These  gases  exist  in  the  air  as  free  gases  and  not 
chemically  combined.  The  air  is  simply  a  mixture  of  these  two 
gases. 

There  is  a  difference  between  a  mixture  and  a  compound. 
In  a  mixture  there  is  no  chemical  change  in  the  molecules  of 
the  substances  mixed.  In  a  compound  there  has  been  a  re- 
arrangement of  the  atoms,  new  molecules  are  formed,  and  a  new 
substance  is  the  result. 

About  ninety-nine  and  one-half  per  cent,  of  air  is  oxygen 
and  nitrogen,  and  one-half  per  cent  is  chiefly  carbon  dioxide. 
Carbon  dioxide  is  a  product  of  combustion,  decay,  and  animal 
exhalation.  It  is  poison  to  the  animal,  but  food  for  the  vege- 
table. The  proportion  in  the  air  is  so  small  however,  that  its 
baneful  influence  upon  animal  life  is  reduced  to  a  minimum. 
The  nitrogen  is  an  inert,  odorless  gas,  and  its  use  in  the  air 
seems  to  be  to  dilute  it,  so  that  man  and  animals  can  breathe 
it.  If  all  the  nitrogen  were  extracted  from  the  air  and  only 
17  257 


258  ACHIEVEMENTS  IN  SCIENCE 

the  oxygen  left  to  breathe,  all  animal  life  would  be  stimulated 
to  death  in  a  short  time.  The  presence  of  the  nitrogen  pre- 
vents too  much  oxygen  from  being  taken  into  the  system  at 
once. 

Air  contains  more  or  less  moisture  in  the  form  of  vapor ; 
this  subject,  however,  will  be  discussed  more  fully  under  the 
head  of  evaporation.  The  air  at  sea-level  weighs  fifteen  pounds 
to  the  square  inch,  and  if  the  whole  envelope  of  air  were  homo- 
geneous— the  same  in  character — it  would  reach  only  about  five 
miles  high.  But  as  it  becomes  gradually  rarefied  as  we  ascend 
it  probably  extends  in  a  very  thin  state  to  a  height  of  eighty  or 
ninety  miles ;  at  least,  at  that  height  we  should  find  a  more 
perfect  vacuum  than  can  be  produced  by  artificial  means.  The 
weight  of  all  the  air  on  the  globe  would  be  eleven  and  two- 
thirds  trillion  pounds  if  no  deduction  had  to  be  made  for  space 
filled  by  mountains  and  land  above  sea-level.  As  it  is,  the 
whole  bulk  weighs  something  less  than  the  above  figures. 

The  air  envelopes  the  globe  to  a  height  at  sea-level  of  eight] 
or  ninety  miles,  gradually  thinning  out  into  the  ether  that  fills 
all  interstellar  space.  We  live  and  move  on  the  bottom  of  a 
great  ocean  of  air.  The  birds  fly  in  it  just  as  the  fish  swim  in 
the  ocean  of  water.  Both  are  transparent  and  both  have 
weight.  Water  in  the  condensed  state  is  heavier  than  the 
air  and  will  seek  the  lowest  places,  but  when  vaporized,  as  in 
the  process  of  evaporation,  it  is  lighter  than  air  and  floats  up- 
ward. In  the  vapor  state  it  is  transparent  like  steam.  If 
you  study  a  steam  jet  you  will  notice  that  for  a  short  dis- 
tance after  it  issues  from  the  boiler  it  is  transparent,  but  soon 
it  condenses  into  cloud. 

If  we  could  see  inside  of  a  boiler  in  which  steam  had  been 
generated,  all  the  space  not  occupied  with  water  would  seem  to 
be  vacant,  since  steam,  before  it  is  condensed,  is  as  transparent 
as  the  air.  We  will,  however,  speak  of  this  subject  more  fully 
under  the  head  of  evaporation  and  cloud  formation.  It  is  not 
enough  that  we  have  the  air  in  which  we  live  and  move,  with 
all  of  its  properties,  as  we  have  described :  something  more  is 
needed  which  is  absolutely  essential  both  to  animal  and  vege- 
table life— and  this  essential  is  motion.  If  the  air  remained 


PHYSICAL   GEOGRAPHY  259 

perfectly  still  with  no  lateral  movement  or  upward  and  down- 
ward currents  of  any  kind,  we  should  have  a  perfectly  constant 
condition  of  things  subjected  only  to  such  gradual  changes  as 
the  advancing  and  receding  seasons  would  produce  owing  to 
the  change  in  the  angle  of  the  sun's  rays.  No  cloud  would 
ever  form,  no  rain  would  ever  fall,  and  no  wind  would  ever 
blow.  It  is  of  the  highest  importance  not  only  that  the  wind 
shall  blow,  but  that  comparatively  sudden  changes  of  tempera- 
ture take  place  in  the  atmosphere,  in  order  that  vegetation  as 
well  as  animal  life  may  exist  upon  the  surface  of  the  globe. 
The  only  place  where  animal  life  could  exist  would  be  in  the 
great  bodies  of  water,  and  it  is  even  doubtful  if  water  could  re- 
main habitable  unless  there  were  means  provided  for  constant 
circulation — motion. 

The  mobility  of  the  atmosphere  is  such  that  the  least  influ- 
ence that  changes  its  balance  will  put  it  in  motion.  While  we 
can  account  in  a  general  way  for  atmospheric  movements,  there 
are  many  problems  relating  to  the  details  that  are  unsolved. 
We  find  that  even  the  "  weather  man  "  makes  mistakes  in  his 
prognostications ;  so  true  is  this  that  it  is  never  safe  to  plan  a 
picnic  for  to-morrow  based  upon  the  predictions  of  to-day. 
The  chief  difficulty  in  the  way  of  solving  the  great  problems 
relating  to  the  sudden  changes  in  the  weather  and  temperature 
lies  in  the  fact  that  two- thirds  or  more  of  the  earth's  surface  is 
covered  with  water;  thus  making  it  impossible  to  establish 
stations  for  observations  that  would  be  evenly  distributed  all 
over  the  earth's  surface.  Enough  is  known,  however,  to  make 
the  study  of  meteorology  a  most  wonderfully  interesting  subject. 

Air  is  composed  chiefly  of  a  mixture  of  oxygen  and  nitro- 
gen, with  a  small  amount  of  carbon  dioxide.  So  far  as  the  life 
and  health  of  the  animal  is  concerned  we  could  get  along  with- 
out this  latter  substance,  but  it  seems  to  be  a  necessity  in  the 
growth  of  vegetation.  There  are  other  things  in  the  air  which, 
while  they  are  unnecessary  for  breathing  purposes,  it  will  be 
well  for  us  to  understand,  as  some  of  them  are  things  to  be 
avoided  rather  than  inhaled. 

As  before  mentioned,  air  contains  moisture,  which  is  a  very 
variable  quantity.  In  a  cold  day  in  winter  it  is  not  more  than 


260 


ACHIEVEMENTS  IN  SCIENCE 


one-thousandth  part,  while  in  a  warm  day  in  summer  it  may 
equal  one-fortieth  of  the  quantity  of  air  in  a  given  space. 
There  is  also  a  small  amount  of  ammonia,  perhaps  not  over  one- 
sixty-millionth.  Oxygen  also  exists  in  the  air  in  very  small 
quantities  in  another  form  called  ozone.  One  way  to  produce 
ozone  is  by  passing  an  electric  spark  through  air.  Any  one 
who  has  operated  a  Holtz  machine  has  noticed  a  peculiar  smell 
attending  the  disruptive  discharges,  which  is  the  odor  of  ozone. 
It  is  what  chemists  call  an  allotropic  form  of  oxygen,  just  as 
the  diamond,  graphite,  and  charcoal  are  all  different  forms  of 
carbon,  and  yet  the  chemical  differences  are  scarcely  traceable. 
It  is  more  stimulating  to  breathe  than  oxygen,  and  is  probably 
produced  by  lightning  discharges. 

The  oxygen  of  the  air  is  consumed  by  all  processes  of  com- 
bustion, and  in  this  we  include  the  breathing  of  men  and  ani- 
mals and  the  decay  of  vegetable  matter,  as  well  as  the  more 
active  combustion  arising  from  fires.  A  grown  person  con- 
sumes something  over  four  hundred  gallons  of  oxygen  per  day, 
and  it  is  estimated  that  all  the  fires  on  the  earth  consume  in  a 
century  as  much  oxygen  as  is  contained  in  the  air  over  an  area 
of  seventy  miles  square.  All  of  these  processes  are  throwing 
into  the  air  carbon  dioxide  (carbonic  acid),  which,  however,  is 
offset  by  the  power  of  vegetation  to  absorb  it ;  thus  the  carbon 
is  retained  and  forms  a  part  of  the  woody  fiber,  and  pure  oxy- 
gen is  given  back  into  the  air.  By  this  process  the  normal 
conditions  of  the  air  are  maintained. 

One  decimeter  (nearly  four  inches)  square  of  green  leaves 
will  decompose  in  one  hour  seven  cublic  centimeters  of  carbon 
dioxide,  if  the  sun  is  shining  on  them ;  in  the  shade  the  same 
area  will  absorb  about  three  in  the  same  time. 

The  air  contains  another  substance  called  bacteria  in  the 
form  of  vegetable  germs.  At  one  time  these  were  supposed  to 
be  low  forms  of  animal  life,  but  it  is  now  determined  that  they 
are  the  lowest  forms  of  vegetable  germs.  Bacteria  is  the  gen- 
eral or  generic  name  for  a  large  class  of  germs,  many  of  them 
disease  germs.  By  analysis  of  the  air  in  different  locations  and 
in  different  parts  of  the  country  it  has  been  determined  that  on 
the  ocean  and  on  the  mountain  tops  these  germs  average  only 


PHYSICAL    GEOGRAPHY  261 

one  to  each  cubic  yard  of  air.  In  the  streets  of  the  average 
city  there  are  3,000  of  them  to  the  cubic  yard,  while  in  other 
places  where  there  is  sickness,  as  in  a  hospital  ward,  there  may 
be  as  many  as  80,000  to  the  cubic  yard.  These  facts  go  to 
prove  what  has  long  been  well  known,  that  the  air  of  a  city 
furnishes  many  more  fruitful  sources  for  disease  than  that  of 
the  country.  Some  forms  of  bacterial  germs  are  not  considered 
harmful,  and  they  probably  perform  even  a  useful  service  in 
the  economy  of  nature.  Within  certain  limits,  other  things 
being  equal,  the  higher  one's  dwelling  is  located  above  the  com- 
mon level  the  purer  will  be  the  air.  This  rule,  however,  has  its 
limits,  as  the  oxygen  of  the  air  is  heavier  than  the  nitrogen,  so 
that  the  air  at  very  great  altitudes  has  not  the  same  proportion 
of  oxygen  to  nitrogen  that  it  has  at  a  lower  level.  An  analysis 
that  was  made  some  years  ago  of  the  air  on  the  west  shore  of 
Lake  Michigan,  especially  that  section  where  the  bluffs  are 
high,  shows  that  it  compares  favorably  with  that  of  any  other 
portion  of  the  United  States. 

In  view  of  the  foregoing,  it  is  of  the  highest  importance  to 
the  sanitary  condition  of  any  city,  town,  or  village  that  it  be 
not  too  compactly  built.  If  more  than  a  certain  number  of 
people  occupy  a  given  area,  it  is  absolutely  impossible  to  pre- 
serve perfect  sanitary  conditions.  And  there  ought  to  be  a 
State  law,  especially  for  all  suburban  towns,  which  are  the 
homes  and  sleeping  places  for  large  numbers  of  business  men 
who  spend  their  days  in  the  foul  air  of  the  city,  stipulating  that 
the  houses  shall  be  not  less  than  a  certain  distance  apart. 
Oxygen  is  the  great  purifier  of  the  blood,  and  if  one  does  not 
get  enough  of  it  he  suffers,  even  though  he  breathes  no  impuri- 
ties. The  power  to  resist  the  effects  of  bad  air  is  much  greater 
when  one  is  awake  and  active  than  when  asleep,  and  this  is 
why  it  is  more  important  to  sleep  in  pure  air  than  to  be  in  it 
during  our  waking  hours.  It  is  best,  however,  to  be  in  good 
air  all  of  the  time.  By  pure  air  I  do  not  mean  pure  oxygen, 
but  the  right  mixture  of  the  two  gases  that  make  air.  Too 
much  of  a  good  thing  is  often  worse  that  not  enough.  Pure 
food  to  eat,  pure  water  to  drink,  and  pure  air  to  breathe  would 
soon  be  the  financial  ruin  of  a  large  class  of  doctors. 


PHYSICAL  GEOGRAPHY 


Wind — Why  It  Blows 

By  ELISHA  GRAY 

LOBULES  of  moisture,  released  by  the  action  of  the  sun's 
rays  in  the  process  of  evaporation,  tend  to  rise,  because 
they  are  lighter  than  the  air.  All  material  substances  have 
weight;  even  hydrogen,  the  lightest  known  gas,  has  weight, 
and  is  attracted  by  gravitation.  If  there  were  no  air  or  other 
gaseous  substances  on  the  face  of  the  earth  except  hydrogen, 
it  would  be  attracted  to  and  envelop  the  earth  the  same  as  the 
air  now  does.  Carbon  dioxide  is  a  gas  that  is  heavier  than  the 
air.  If  we  take  a  vessel  filled  with  this  gas  and  pour  it  into 
another  vessel  it  will  sink  to  the  bottom  and  displace  the  air 
contained  in  it  until  the  air  is  all  driven  out.  If  we  fill  a  jar 
with  water  up  to  a  certain  height  and  then  pour  a  pint  of  shot 
into  it  the  water  will  be  caused  to  rise  in  the  vessel  because  it 
has  been  displaced  at  the  bottom  by  the  heavier  material. 
Now  if  we  remove  the  shot,  the  water  will  recede  to  the  level 
maintained  before  the  shot  was  put  in.  On  the  contrary,  if  we 
should  pour  an  equal  bulk  of  cork  or  pith  balls  into  the  jar,  the 
water  would  not  be  displaced,  because  the  balls  are  lighter  than 
the  water  and  would  lie  on  top  of  it ;  if,  however,  the  water  is 
removed  from  the  jar,  the  cork  will  immediately  go  to  the  bot- 
tom of  the  jar,  because  the  cork  is  heavier  than  the  air  which 
has  taken  the  place  of  the  water.  We  wish  to  impress  upon 
the  mind  of  the  reader  the  fact,  that  all  substances  of  a  fluid 
nature,  whether  in  the  fluid  or  gaseous  state,  have  weight,  and 
obey  the  laws  of  gravity,  while  the  heavier  portions  will  always 
seek  the  lower  levels,  and  in  doing  this  will  displace  the  lighter 

262 


PHYSICAL    GEOGRAPHY  263 

portions,  causing  them  to  rise.  There  is  no  tendency  in  any 
substance  to  rise  of  itself,  but  the  lighter  substance  rises  be- 
cause it  is  forced  to  do  so  by  the  heavier,  which  displaces  it. 
This  law  lies  at  the  bottom  of  all  the  phenomena  of  air  currents. 

If  we  are  at  certain  points  on  the  seashore  in  the  summer 
time  we  may  notice  that  about  nine  o'clock  in  the  morning  a 
breeze  will  spring  up  from  the  ocean  and  blow  toward  the  land ; 
this  will  increase  in  intensity  until  about  two  o'clock  in  the 
afternoon,  when  it  has  reached  its  maximum  velocity,  and  from 
this  time  it  gradually  diminishes,  until  in  the  evening  there  will 
be  a  season  of  calm,  the  same  as  there  was  in  the  early  morn- 
ing. The  explanation  of  this  peculiar  action  of  the  air  is  found 
in  the  fact  that  during  the  day  the  land  is  heated  much  more 
rapidly  on  its  surface  than  the  water  is. 

The  radiant  energy  from  the  sun  is  suddenly  arrested  at 
the  surface  of  the  earth,  which  is  heated  to  only  a  very  shallow 
depth,  while  in  the  water  it  is  different ;  being  transparent  it  is 
penetrated  by  the  radiant  energy  to  a  much  greater  depth  and 
does  not  suddenly  arrest  it,  as  is  the  case  on  land.  As  the  sun 
rises  and  the  rays  strike  in  a  more  and  more  vertical  direction, 
the  earth  becomes  rapidly  and  intensely  heated  at  its  surface, 
and  this  in  turn  heats  the  stratum  of  air  next  above  it,  which 
is  pressing  on  it  with  a  force  of  fifteen  pounds  to  the  square 
inch  at  sea-level.  When  air  is  heated  it  expands,  and  as  it  ex- 
pands it  grows  lighter.  The  stratum  lying  upon  the  earth  as 
soon  as  it  becomes  heated  moves  upward  and  its  place  is  occu- 
pied by  the  heavier,  cooler  air  that. flows  in  from  the  sides. 
We  can  now  see  that  if  there  is  a  strong  ascending  current  of 
air  on  the  land  near  the  ocean  the  cooler  air  from  the  surface 
of  the  ocean  will  flow  in  to  take  the  place  of  the  warmer  and 
lighter  air  that  is  driven  upward,  really  by  the  force  of  gravity 
which  causes  the  heavier  fluid  to  keep  the  lowest  level.  As 
the  earth  grows  hotter  this  movement  is  more  and  more  rapid, 
which  causes  the  flow  of  colder  air  to  be  quickened,  and  hence 
the  increasing  force  of  the  wind  as  the  sun  mounts  higher  in 
the  heavens.  But  when  it  has  passed  the  point  of  maximum 
heating  intensity  and  the  earth  begins  to  cool  by  radiation,  the 
movements  of  air  currents  begin  to  slow  up,  until  along  in  the 


264  ACHIEVEMENTS  IN  SCIENCE 

evening  a  point  is  reached  where  the  surface  of  the  earth  and 
that  of  the  ocean  are  of  equal  temperature,  and  there  is  no 
longer  any  cause  for  change  of  position  in  the  air. 

The  earth  heats  up  quickly,  and  it  also  cools  quickly,  espe- 
cially if  there  is  green  grass  and  vegetation.  While  they  are 
poor  conductors  of  heat,  they  are  excellent  radiators,  so  that 
when  the  sun's  rays  are  no  longer  active  the  earth  cools  down 
rapidly  and  soon  passes  the  point  where  there  is  an  equilibrium 
between  the  land  and  water.  The  water  possesses  the  opposite 
quality.  It  is  slow  to  become  heated,  because  of  a  much  larger 
mass  that  is  affected,  and  is  equally  slow  to  give  up  the  heat. 
And  the  consequence  is,  that  after  the  sun  has  set  the  land 
cools  so  much  faster  than  the  water  that  we  soon  have  the 
opposite  condition,  and  the  sea  is  warmer  than  the  land,  which 
makes  the  air  at  that  point  lighter,  and  which  in  turn  causes 
the  denser  or  colder  air  from  the  land  to  flow  toward  the  ocean, 
and  displace  the  lighter  air  and  force  it  upward ;  hence  we  have 
a  land  instead  of  a  sea  breeze.  So  that  the  normal  condition  in 
summer  is  that  of  a  breeze  from  the  ocean  toward  the  land  dur- 
ing part  of  the  day  and  a  corresponding  breeze  from  the  land 
to  the  ocean  during  part  of  the  night,  with  a  period  of  no  wind 
during  the  morning  and  evening  of  each  day. 

The  forces  that  work  to  produce  all  the  varying  phenomena 
of  air  currents  on  different  portions  of  the  earth  are  difficult  to 
explain,  as  there  are  so  many  local  conditions  of  heat  and  cold, 
and  these  are  modified  by  the  advancing  and  receding  seasons. 
The  unequal  distribution  of  land  and  water  upon  the  earth's 
surface;  the  readiness  with  which  some  portions  absorb  and 
radiate  heat  as  compared  with  others ;  the  tall  ranges  of  moun- 
tains, many  of  them  snow-capped;  the  lowlands  adjacent  to 
them  that  become  intensely  heated  under  the  sun's  rays ;  the 
diversity  of  coast-line  and  the  fact  that  there  is  a  zone  of  con- 
tinually heated  earth  and  water  in  the  tropical  regions — all 
these  conditions,  coupled  with  the  fact  that  the  earth  rotates 
on  its  axis  once  in  twenty-four  hours,  are  certainly  sufficient  to 
account  for  all  the  complicated  phenomena  of  aerial  changes  on 
the  various  portions  of  the  earth's  surface. 

The  trade  winds  are  so  called  because  they  blow  in  a  certain 


PHYSICAL   GEOGRAPHY  265 

definite  direction  during  certain  seasons  of  the  year,  and  can  be 
reckoned  upon  for  the  use  of  commerce.  If  you  trace  the  line 
of  the  equator  you  will  notice  that  for  more  than  three-quarters 
of  the  distance  it  passes  through  the  water.  The  water  be- 
comes gradually  heated  to  a  considerable  depth,  and  when  once 
saturated  with  heat  is  slow  to  give  it  up.  It  can  easily  be  seen 
that  there  will  be  a  zone  extending  each  way  from  the  equator 
for  a  certain  distance  that  will  become  more  intensely  heated 
than  any  other  parts  of  the  earth,  with  the  exception  of  certain 
circumscribed  portions  of  the  land.  The  result  is  that  this 
heated  equatorial  zone  is  constantly  sending  up  warm  air  caused 
by  the  inrush  of  colder  air,  which  is  heavier  than  the  air  at  the 
equator,  expanded  by  the  heat.  The  warm  air  at  the  equator 
is  forced  up  into  higher  regions  of  the  atmosphere,  and  here 
it  overflows  each  way,  north  and  south,  causing  a  current 
of  air  in  the  upper  regions  counter  to  that  of  the  lower.  As  it 
travels  north  and  south  it  gradually  drops  as  it  becomes  cooler, 
and  finally  at  some  point  north  and  south  its  course  is  changed 
and  it  flows  in  again  toward  the  equator.  As  a  matter  of  fact, 
the  trade  winds  do  not  flow  apparently  from  the  north  and 
south  directly  toward  the  equator,  but  in  an  oblique  direction. 
On  the  north  side  of  the  equator  we  have  a  northeasterly 
wind,  and  a  southeasterly  wind  on  the  south  side.  This  is 
caused  by  the  rotation  of  the  earth  from  west  to  east.  The 
direction  of  the  trade  wind,  however,  is  more  apparent  than 
real. 

The  earth  in  its  diurnal  revolutions  travels  at  the  rate  of  a 
little  more  than  1,000  miles  an  hour  at  the  equator.  But  if  we 
should  travel  northward  to  within  four  miles,  say,  of  the  north 
pole,  the  surface  point  would  be  moving  at  the  rate  of  only 
about  a  mile  an  hour.  At  some  point  equidistant  between  the 
north  pole  and  the  equator  the  surface  of  the  earth  will  be 
moving  at  a  rate,  say,  of  five  hundred  miles  an  hour.  If  we 
could  fire  a  projectile  from  this  point  that  would  have  a  carry- 
ing power  to  take  it  to  the  equator  some  time  after  the  projec- 
tile was  fired,  although  it  would  fly  in  a  perfectly  direct  line,  it 
would  appear  to  any  one  at  the  equator  to  be  moving  from  a 
northeasterly  direction.  The  reason  is  that  the  earth  is  travel- 


266  ACHIEVEMENTS  IN  SCIENCE 

ing  twice  as  fast  at  the  equator  as  it  is  at  the  point  whence  the 
projectile  is  fired.  Therefore  it  will  overshoot,  so  to  speak,  at 
the  equator,  and  not  be  dragged  around  by  the  increased  motion 
we  find  there. 

To  make  this  still  plainer,  suppose  the  earth  to  be  standing 
still  and  a  projectile  be  fired  directly  across  from  the  north  pole 
in  the  direction  of  the  lines  of  longitude  and  required  one  hour 
to  reach  the  equator,  the  projectile  would  appear  to  any  one 
standing  at  the  equator  to  come  directly  from  the  north.  If, 
however,  the  earth  is  revolving  to  the  eastward  at  the  rate  of 
1,000  miles  an  hour  at  the  equator,  and  the  projectile  was 
fired  from  the  pole,  where  there  is  practically  no  motion,  in 
the  same  direction  along  the  longitudinal  lines  as  before,  the 
observer  would  have  to  be  in  a  position  of  the  equator  1,000 
miles  west  of  this  longitudinal  line,  in  order  to  see  the  pro- 
jectile when  it  arrived;  therefore  the  apparent  movement  of 
the  projectile  would  not  be  along  the  line  at  the  instant  that  it 
was  fired,  but  along  a  line  that  would  cross  the  equator  at  a 
point  1,000  miles  west.  When  a  southward  impulse  is  given 
to  the  air  it  follows,  to  some  extent,  the  same  law,  so  that 
to  one  standing  on  the  equator  the  northern  trade  wind  will 
blow  from  the  northeast  and  the  southern  trade  wind  from  the 
southeast. 

Owing  to  the  fact  that  the  air  rises  in  the  heated  zone  there 
is  always  a  region  of  calms  at  this  point  where  there  is  no  wind 
and  no  rain.  There  are  two  other  regions  of  calms  in  the 
ocean,  one  at  the  north  at  the  tropic  of  Cancer  and  another  at 
the  south  near  the  tropic  of  Capricorn.  As  has  been  stated, 
there  are  currents  flowing  back  in  the  upper  regions  at  the 
equator  north  and  south,  and  these  are  called  the  upper  trades 
— the  lower  currents  being  called  the  lower  trades.  These 
upper  trades  gradually  fall  till  they  reach  the  tropic  of  Cancer 
on  the  north,  where  the  lower  part  of  the  current  stops  and 
bends  back  toward  the  equator,  now  becoming  a  part  of  the 
lower  trade  wind.  This  causes  a  calm  at  that  point  where  it 
turns.  The  upper  parts  of  this  current  continue  on,  in  a 
northerly  and  southerly  direction,  on  the  surface  until  they 
meet  with  the  cold  air  of  the  north  and  south  polar  regions, 


PHYSICAL   GEOGRAPHY 


267 


where  there  is  a  conflict  of  the  elements — as  there  always  is 
when  cold  and  warm  currents  meet. 

The  only  point  where  the  trade  wind  has  free  play  is  in  the 
South  Indian  Ocean,  and  this  is  called  the  "heart  of  the 
trades." 

If  the  whole  globe  were  covered  with  water  there  would  be 
a  more  constant  condition  of  temperature ;  but  owing  to  the 
great  difference  between  the  land  and  water,  both  as  to  altitude 
and  the  ability  to  absorb  and  radiate  heat,  we  have  all  of  these 
varied  and  complicated  conditions  of  wind  and  weather.  The 
trade  winds  shift  from  north  to  south  and  vice  versa  with  the 
advancing  and  receding  seasons,  due  to  the  fact  that  the  earth 
has  a  compound  motion.  It  not  only  revolves  on  its  axis  once 
in  twenty-four  hours,  but  it  also  travels  around  the  sun  once  a 
year ;  and  because  the  axis  of  the  earth  is  not  perpendicular  to 
the  plane  of  its  orbit  around  the  sun,  the  earth  seems  to  rock 
back  and  forth  in  the  direction  of  its  axis  once  a  year.  This  is 
only  apparent,  however,  and  not  real. 


PHYSICAL  GEOGRAPHY 


Mirage 

By  ELISHA  GRAY 

ALIGHT-  RAY  in  passing  from  one  transparent  medium 
to  another,  differing  in  density,  is  bent  at  the  point  it 
enters.  This  bending  of  the  light-ray  is  called  refraction.  If 
we  put  a  stick  into  the  water  at  an  angle  with  its  surface  the 
stick  will  appear  to  bend  upward  at  the  point  it  enters  the 
water,  while  the  light-ray  really  bends  downward. 

To  illustrate  this  phenomenon  place  a  tank,  something  like 
an  aquarium,  filled  with  water,  in  a  dark  room.  Admit  a  small 
beam  of  sunshine  through  the  shutter,  striking  the  top  of  the 
water  at  an  angle,  say,  of  forty-five  degrees.  If  the  room  is 
dark  you  can  see  the  beam  of  light  as  it  passes  through  the  air, 
for  it  illuminates  the  particles  of  dust  floating  in  the  air.  When 
it  strikes  the  surface  of  the  water  it  is  bent  downward.  Now 
let  us  put  a  coin  on  the  bottom  of  the  tank  just  where  the 
beam  of  light  strikes  it,  and  put  a  screen  of  some  opaque  sub- 
stance on  the  side  of  the  tank  from  which  the  beam  of  light 
comes,  and  raise  it  up  till  it  just  touches  the  lower  edge  of  the 
light-ray.  Stretch  a  string  along  the  path  of  the  beam  of  light 
and  fasten  it  at  both  ends — so  as  to  mark  its  angle  and  posi- 
tion. Now  open  the  shutter  and  flood  the  room  with  light ; 
place  your  eye  in  the  path  of  the  beam  that  is  now  marked  by 
the  string  and  you  can  see  the  coin  at  the  bottom  of  the  tank, 
although  it  is  really  hidden  by  the  screen,  if  you  look  toward  it 
in  a  straight  line.  The  coin  will  appear  to  be  in  a  direct  line 
with  the  string,  but  it  is  not. 

Leave  the  string,  coin,  and  screen  in  position,  and  run  the 

268 


! 


PHYSICAL   GEOGRAPHY  269 

water  off,  and  then  place  your  eye  in  the  same  position  as  be- 
fore when  you  saw  the  coin,  and  you  will  find  that  you  cannot 
see  it,  for  it  is  hidden  behind  the  screen.  Draw  a  line  to  the 
bottom  of  the  tank  in  line  with  the  string,  and  the  point  where 
it  strikes  the  bottom  is  where  the  coin  appeared  to  be.  Place 
another  coin  at  this  point  so  that  you  can  just  see  it  over  the 
top  of  the  screen  if  you  look  from  the  same  point  as  before. 
Now  fill  the  tank  with  water  again  and  look  from  the  same 
view-point,  arid  lo !  the  first  coin  has  come  into  view  in  line 
with  the  string,  while  the  second  has  moved  forward  out  of  line 
with  the  string.  You  observe,  then,  that  by  this  means  we  can 
see  around  a  corner.  But  the  object  under  these  conditions  is 
never  where  it  appears  to  be,  for  it  will  always  appear  to  be  in 
a  direct  line  with  the  direction  that  the  light-ray — that  is  re- 
flected from  the  object — enters  the  eye. 

Light  is  refracted  differently  in  different  media.     It  is  re- 
fracted as  it  passes  through  the  air  unless  the  air  is  the  same 
density  all  the  way  from  the  object  to  the  eye.     If  we  are  look- 
through  the  air  and  there  is  a  gradual  change  of  density 
tween  us  and  the  object  we  see,  there  will  be  a  gradual  curve 
the  reflected  light  coming  from  the  object  to  us,  and  the 
ject  will  appear  to  be  in  the  direction  that  the  light  enters 
ur  eyes.     The  distance  its  true  position  will  be  from  where  it 
ppears  to  be  will  depend  upon  the  amount  of  change  in  the 
ensity  of  the  media  through  which  we  are  looking.    This  phe- 
omenon  we  call  mirage.     Many  times  those  of  us  who  live  on 
e  lakeshore  have  seen  this  phenomenon  when  looking  off  on 
e  horizon  on  a  summer  day.     Sometimes  the  sand-hills  of 
ichigan  City,  on  the  east  shore  of  Lake  Michigan,  may  be 
seen  from  the  opposite  shore  looming  up  in  the  air,  when  in 
fact  a  straight  line  drawn  from  a  point  on  the  shore  at  Michigan 
City  and  elevated  just  enough  to  clear  the  surface  of  the  water 
would  clear  the  tree-tops  on  the  opposite  shore.     So  that  when 
we  see  the  sand-hills  from  the  west  shore  we  see  by  curved 
rays  of  light  extending  across  the  lake.     Sometimes  an  image 
of  the  water-line  on  the  horizon  will  be  thrown  up  into  the  air 
with  perhaps  a  picture  of  a  ship  on  it,  and  often  we  can  see  the 
sky  under  the  ship-picture,  but  not  the  ship  itself,  of  which  that 


270  ACHIEVEMENTS  IN  SCIENCE 

is  a  reflection.  Many  times  we  see  the  sun  after  it  is  below 
the  horizon,  by  these  refracted  rays. 

There  is  another  phenomenon  called  mirage,  that  may  be 
seen  on  sandy  plains  or  deserts  on  any  very  hot  day.  The 
sand  becomes  very  much  heated,  and  a  stratum  of  heated  air  is 
formed  close  to  the  ground  which  makes  the  density  of  the  air 
increase  upward,  for  a  distance,  forming  a  line  of  condensation 
which  acts  as  a  reflecting  surface  for  light,  and  it  has  the  ap- 
pearance of  smooth  water.  Any  one  seeing  it  for  the  first  time 
will  declare  that  it  is  water,  and  in  fact  the  deception  is  perfect, 
as  I  have  occasion  to  know.  I  was  once  traveling  through 
what  is  called  Smoky  Valley,  in  Nevada,  on  a  hot  day.  About 
two  o'clock  in  the  afternoon  we  came  in  sight  of  a  large  body 
of  water  many  miles  in  extent,  as  it  appeared  to  me.  It  was  a 
lake  of  wondrous  beauty,  with  a  smooth  surface.  The  moun- 
tains and  trees  were  reflected  in  the  water  in  inverted  position, 
as  all  of  us  have  seen  in  other  bodies  of  smooth  water.  I 
imagined  that  I  could  see  towns  and  cities  scattered  along  the 
distant  shores,  and  the  deception  was  so  perfect  that  for  the 
time  I  could  not  believe  it  was  not  what  it  seemed.  My  com- 
panions were  natives,  and,  knowing  that  I  was  a  "  tenderfoot," 
were  disposed  to  have  a  little  fun ;  and  they  had  it.  They  had 
names  for  the  towns,  as  well  as  the  lake,  and  I  got  a  lot  of  in- 
formation regarding  the  industries  carried  on  there.  I  could 
discern  sails  in  the  haze  of  the  distance,  and  imagined  I  could 
see  moving  trains  and  hear  the  whistle  of  locomotives.  After 
I  had  enjoyed  this  spectacle  for  an  hour  or  more,  as  we  jogged 
slowly  along  in  our  wagon,  and  the  natives  had  had  untold  fun 
in  a  quiet  way,  the  whole  thing  suddenly  picked  itself  up  and 
got  out  of  sight.  I  knew  then  that  I  had  been  witnessing  an 
unusually  fine  exhibition  of  mirage  on  the  desert. 

There  is  another  kind  of  mirage  that  is  much  more  common 
than  the  natural  phenomena  that  I  have  been  describing,  and 
while  it  does  not  strictly  belong  in  the  category  of  natural  sci- 
ence, there  is  a  sense  in  which  it  does.  It  may  be  styled  mental 
mirage,  and  consists  in  the  distorted  conceptions  of  various 
subjects  and  things  that  we  see  through  a  distorted  mental 
atmosphere,  which  is  largely  one  of  our  own  creation. 


PHYSICAL    GEOGRAPHY  271 

Man  is  to  a  large  extent  a  creature  of  circumstances  and 
environment;  not  wholly,  as  that  would  take  away  his  free 
agency  and  make  him  in  no  sense  the  architect  of  his  own 
fortune.  Every  man  of  strong  individuality  is  the  latter,  to  a 
large  extent,  but  he  is  a  strong  man  indeed  who  can  successfully 
resist,  first,  the  molding  influence  of  heredity,  and  after  that  the 
almost  irresistible  power  of  education  in  any  particular  line. 
He  cannot  entirely  resist  the  prejudices  of  early  training  and 
surroundings,  whether  they  appeal  to  his  reasoning  powers  or 
not.  This  is  especially  true  when  applied  to  the  dogmas  of  re- 
ligious sects  and  the  so-called  principles  of  political  parties. 
The  average  good  citizen  of  any  religious  sect  or  political  party 
sees  clearly,  in  common  with  his  brethren  of  other  sects  and 
parties,  in  direct  lines  through  the  atmosphere  of  common  in- 
terest, common  brotherhood,  and  sometimes  common  sense. 
But  as  soon  as  the  rays  of  his  mental  vision  strike  some  denser, 
or,  it  may  be,  rarer  medium  of  prejudice  of  party,  church,  or 
society  affiliation,  a  refraction  takes  place,  and  we  have  the 
phenomenon  of  mental  mirage.  The  truth  may  lie  in  a  direct 
line  ahead,  but  he  is  really  seeing  in  a  different  direction  because 
of  the  refracting  or  distorting  power  of  a  prejudice. 

Science  has  no  prejudices — though  scientists  often  do.  Sci- 
ence is  like  figures :  they  do  not  lie  themselves,  but  the  men 
who  figure  are  often  the  greatest  liars  in  the  world.  Science, 
per  se,  is  formulated  truth.  Its  aim  is  to  get  at  the  truth  about 
everything.  Taking  this  view  of  science,  it  is  the  most  impor- 
tant study  that  man  ever  engaged  in.  So  much  of  human 
effort  has  been  and  is  spent  in  combating  things  that  are  non- 
essential,  that  too  little  co-operative  work  is  done  in  the  direc- 
tion of  determining  the  great  essential  truths.  In  one  of  the 
chapters  on  Sound  it  was  shown  how  one  musical  tone  of  the 
same  power  and  pitch,  and  even  of  the  same  quality,  as  that  of 
another  just  like  it,  might  be  entirely  obliterated  by  the  man- 
ner in  which  they  were  sounded  in  relation  to  each  other.  It 
was  also  shown  that  there  was  an  easier  way  to  sound  both  to- 
gether so  that  each  would  re-enforce  the  other  and  thus  double 
the  tone  instead  of  the  one  entirely  destroying  the  efficiency  of 
the  other.  So  it  is  with  human  effort.  Co-operation  will  ac- 


272  ACHIEVEMENTS  IN  SCIENCE 

complish  wonders  for  good,  while  the  opposite  only  leaves  a 
dark  void  that  is  the  darker  because  of  the  misguided  effort  put 
forth,  that  other  men  have  not  only  seen,  but  of  which  they 
have  also  felt  the  blighting  influence. 

Another  phase  of  mirage,  as  seen  in  natural  phenomena,  is 
its  complete  deceptiveness  and  its  ability,  owing  to  the  peculiar 
atmosphere  by  which  it  is  surrounded,  to  stimulate  the  imagina- 
tion. In  the  hazy  outlines  ghosts  of  shapes  become  real  things, 
and  the  heated  wave-motion  of  the  atmosphere  easily  gives  life 
to  imaginary  men  and  animals  and  motion  to  sailing  vessels  and 
steam-cars.  Mental  mirage  is  more  potent  in  its  deceptive- 
ness  and  more  powerful  in  its  influence  over  the  imagination 
than  its  counterpart  in  the  natural  world ;  and  has  the  disad- 
vantage of  not  yielding  so  readily  to  the  power  of  analysis  and 
being  so  susceptible  of  explanation.  One  of  the  great  advan- 
tages derived  from  the  study  of  natural  science  is,  that  it  is 
usually  studied  for  its  own  sake  and  for  the  object  of  arriving 
at  the  truth  whatever  it  is.  The  scientific  investigator  must 
have  no  prejudice  not  founded  on  fact,  and  when  so  founded  it 
is  no  longer  a  prejudice.  He  must  not  allow  the  religious 
dogma  or  the  political  principle  to  enter  or  become  one  of  the 
factors  in  his  search  for  truth,  but  when  he  has  found  the  truth 
it  may  shape  the  dogma,  destroy  or  confirm  the  political  princi- 
ple, according  as  they  are  found  to  be  in  or  out  of  harmony 
with  the  facts.  Facts  are  stubborn  things,  and  it  is  worse  than 
useless  to  try  to  ignore  them  when  once  established.  The 
man  who  uses  scientific  methods  in  studying  all  questions  is  a 
much  safer  man  to  follow  than  the  man  who  starts  out  with 
certain  preconceived  notions  of  things.  The  former  throws 
away  all  prejudice  in  his  investigations,  while  the  latter  is  con- 
stantly trying  to  find  something  to  bolster  up  his  preconceived 
notions.  He  generally  thinks  he  finds  what  he  is  seeking  for, 
but  he  usually  finds  them  through  the  refracted  vision  of  mental 
mirage. 


PHYSICAL  GEOGRAPHY 


I 
I 


Rain  and  Snow 

By  JOHN  TYNDALL 

AT  the  equator,  and  within  certain  limits  north  and  south  of 
it,  the  sun  at  certain  periods  of  the  year  is  directly  over- 
head at  noon.  These  limits  are  called  the  Tropics  of  Cancer 
and  of  Capricorn.  Upon  the  belt  comprised  between  these 
two  circles  the  sun's  rays  fall  with  their  mightiest  power;  for 
here  they  shoot  directly  downward,  and  heat  both  earth  and 
sea  more  than  when  they  strike  slantingly. 

When  the  vertical  sunbeams  strike  the  land  they  heat  it, 
and  the  air  in  contact  with  the  hot  soil  becomes  heated  in  turn, 
ut  when  heated  the  air  expands,  and  when  it  expands  it  be- 
mes  lighter.     This  lighter  air  rises,  like  wood  plunged  into 
rater,  through  the  heavier  air  overhead. 

When  the  sunbeams  fall  upon  the  sea  the  water  is  warmed, 
though  not  so  much  as  the  land.  The  warmed  water  expands, 
becomes  thereby  lighter,  and  therefore  continues  to  float  upon 
the  top.  This  upper  layer  of  water  warms  to  some  extent  the 
air  in  contact  with  it,  but  it  also  sends  up  a  quantity  of  aqueous 
vapor,  which  being  far  lighter  than  air,  helps  the  latter  to  rise- 
Thus  both  from  the  land  and  from  the  sea  we  have  ascending 
currents  established  by  the  action  of  the  sun. 

When  they  reach  a  certain  elevation  in  the  atmosphere, 
hese  currents  divide  and  flow,  part  toward  the  north  and  part 
toward  the  south ;  while  from  the  north  and  the  south  a  flow 
of  heavier  and  colder  air  sets  in  to  supply  the  place  of  the 
ascending  warm  air. 

Incessant  circulation  is  thus  established  in  the  atmosphere. 
18  273 


274  ACHIEVEMENTS  IN  SCIENCE 

The  equatorial  air  and  vapor  flow  above  toward  the  north  and 
south  poles,  while  the  polar  air  flows  below  toward  the  equator. 
The  two  currents  of  air  thus  established  are  called  the  upper 
and  the  lower  trade  winds. 

But  before  the  air  returns  from  the  poles  great  changes 
have  occurred.  For  the  air  as  it  quitted  the  equatorial  regions 
was  laden  with  aqueous  vapor,  which  could  not  subsist  in  the 
cold  polar  regions.  It  is  there  precipitated,  falling  sometimes 
as  rain,  or  more  commonly  as  snow.  The  land  near  the  pole  is 
covered  with  this  snow,  which  gives  birth  to  vast  glaciers. 

It  is  necessary  that  you  should  have  a  perfectly  clear  view 
of  this  process,  for  great  mistakes  have  been  made  regarding 
the  manner  in  which  glaciers  are  related  to  the  heat  of  the 
sun 

It  was  supposed  that  if  the  sun's  heat  were  diminished, 
greater  glaciers  than  those  now  existing  would  be  produced. 
But  the  lessening  of  the  sun's  heat  would  infallibly  diminish 
the  quantity  of  aqueous  vapor,  and  thus  cut  off  the  glaciers  at 
their  source.  A  brief  illustration  will  complete  your  knowledge 
here. 

In  the  process  of  ordinary  distillation,  the  liquid  to  be  dis- 
tilled is  heated  arid  converted  into  vapor  in  one  vessel,  and 
chilled  and  reconverted  into  liquid  in  another.  What  has  just 
been  stated  renders  it  plain  that  the  earth  and  its  atmosphere 
constitute  a  vast  distilling  apparatus  in  which  the  equatorial 
ocean  plays  the  part  of  the  boiler,  and  the  chill  regions  of  the 
poles  the  part  of  the  condenser.  In  this  process  of  distillation 
heat  plays  quite  as  necessary  a  part  as  cold,  and  before  Bishop 
Heber  could  speak  of  "Greenland's  icy  mountains,"  the  equa- 
torial ocean  had  to  be  warmed  by  the  sun.  We  shall  have  more 
to  say  upon  this  question  afterward. 

The  heating  of  the  tropical  air  by  the  sun  is  indirect.  The 
solar  beams  have  scarcely  any  power  to  heat  the  air  through 
which  they  pass ;  but  they  heat  the  land  and  ocean,  and  these 
communicate  their  heat  to  the  air  in  contact  with  them.  The 
air  and  vapor  start  upward  charged  with  the  heat  thus  com- 
municated. 


PHYSICAL   GEOGRAPHY  275 


TROPICAL  RAINS 

But  long  before  the  air  and  vapor  from  the  equator  reach 
the  poles,  precipitation  occurs.  Wherever  a  humid  warm  wind 
mixes  with  a  cold  dry  one,  rain  falls.  Indeed  the  heaviest  rains 
occur  at  those  places  where  the  sun  is  vertically  overhead.  We 
must  inquire  a  little  more  closely  into  their  origin. 

Fill  a  bladder  about  two-thirds  full  of  air  at  the  sea  level, 
and  take  it  to  the  summit  of  Mount  Blanc.  As  you  ascend, 
the  bladder  becomes  more  and  more  distended ;  at  the  top  of 
the  mountain  it  is  fully  distended,  and  has  evidently  to  bear  a 
pressure  from  within.  Returning  to  the  sea  level  you  find  that 
the  tightness  disappears,  the  bladder  finally  appearing  as  flaccid 
as  at  first. 

The  reason  is  plain.  At  the  sea  level  the  air  within  the 
bladder  has  to  bear  the  pressure  of  the  whole  atmosphere,  being 
thereby  squeezed  into  a  comparatively  small  volume.  In 
ascending  the  mountain,  you  leave  more  and  more  of  the  atmos- 
phere behind ;  the  pressure  becomes  less  and  less,  and  by  its 
expansive  force  the  air  within  the  bladder  swells  as  the  outside 
pressure  is  diminished.  At  the  top  of  the  mountain  the  expan- 
sion is  quite  sufficient  to  render  the  bladder  tight,  the  pressure 
within  being  then  actually  greater  than  the  pressure  without. 
By  means  of  an  air-pump  we  can  show  the  expansion  of  a  bal- 
loon partly  filled  with  air,  when  the  external  pressure  has  been 
in  part  removed. 

But  why  do  I  dwell  upon  this  ?  Simply  to  make  plain  to 
you  that  the  unconfined  air,  heated  at  the  earth's  surface,  and 
ascending  by  its  lightness,  must  expand  more  and  more  the 
higher  it  rises  in  the  atmosphere. 

And  now  I  have  to  introduce  to  you  a  new  fact,  toward 
the  statement  of  which  I  have  been  working  for  some  time.  It 
is  this :  The  ascending  air  is  chilled  by  its  expansion.  Indeed 
this  chilling  is  one  source  of  the  coldness  of  the  higher  atmos- 
pheric regions.  And  now  fix  your  eye  upon  those  mixed  cur- 
rents of  air  and  aqueous  vapor  which  rise  from  the  warm  tropi- 
cal ocean.  They  start  with  plenty  of  heat  to  preserve  the  vapor 


276  ACHIEVEMENTS  IN  SCIENCE 

as  vapor;  but  as  they  rise  they  come  into  regions  already 
chilled,  and  they  are  still  further  chilled  by  their  own  expan- 
sion. The  consequence  might  be  foreseen.  The  load  of  vapor 
is  in  great  part  precipitated,  dense  clouds  are  formed,  their  par- 
ticles coalesce  to  rain-drops,  which  descend  daily  in  gushes  so 
profuse  that  the  word  "  torrential "  is  used  to  express  the  copi- 
ousness of  the  rainfall.  I  could  show  you  this  chilling  by  ex- 
pansion, and  also  the  consequent  precipitation  of  clouds. 

Thus,  long  before  the  air  from  the  equator  reaches  the  poles, 
its  vapor  is  in  great  part  removed  from  it,  having  redescended 
to  the  earth  as  rain.  Still  a  good  quantity  of  the  vapor  is  car- 
ried forward,  which  yields  hail,  rain,  and  snow  in  northern  and 
southern  lands. 

MOUNTAIN  CONDENSERS 

To  complete  our  view  of  the  process  of  atmospheric  precipi- 
tation we  must  take  into  account  the  action  of  mountains. 
Imagine  a  southwest  wind  blowing  across  the  Atlantic  toward 
Ireland.  In  its  passage  it  charges  itself  with  aqueous  vapor. 
In  the  south  of  Ireland  it  encounters  the  mountains  of  Kerry ; 
the  highest  of  these  is  Magillicuddy's  Reeks,  near  Killarney. 
Now  the  lowest  stratum  of  this  Atlantic  wind  is  that  which  is 
most  fully  charged  with  vapor.  When  it  encounters  the  base 
of  the  Kerry  mountains  it  is  tilted  up  and  flows  bodily  over 
them.  Its  load  of  vapor  is  therefore  carried  to  a  height,  it  ex- 
pands on  reaching  the  height,  it  is  chilled  in  consequence  of 
the  expansion,  and  comes  down  in  copious  showers  of  rain. 
From  this,  in  fact,  arises  the  luxuriant  vegetation  of  Killarney ; 
to  this,  indeed,  the  lakes  owe  their  water  supply.  The  cold 
crests  of  the  mountains  also  aid  in  the  work  of  condensation. 

Note  the  consequence.  There  is  a  town  called  Cahirciveen 
to  the  southwest  of  Magillicuddy's  Reeks,  at  which  observations 
of  the  rainfall  have  been  made,  and  a  good  distance  farther  to 
the  northeast,  right  in  the  course  of  the  southwest  wind  there 
is  another  town,  called  Portarlington,  at  which  observations  of 
rainfall  have  also  been  made.  But  before  the  wind  reaches  the 
latter  station  it  has  passed  over  the  mountains  of  Kerry  and 
left  a  great  portion  of  its  moisture  behind  it.  What  is  the  re- 


PHYSICAL   GEOGRAPHY  277 

suit  ?  At  Cahirciveen,  as  shown  by  Dr.  Lloyd,  the  rainfall 
amounts  to  fifty-nine  inches  in  a  year,  while  at  Portarlington  it 
is  only  twenty-one  inches. 

Again,  you  may  sometimes  descend  from  the  Alps  when 
the  fall  of  rain  and  snow  is  heavy  and  incessant,  into  Italy,  and 
find  the  sky  over  the  plains  of  Lombardy  blue  and  cloudless, 
the  wind  at  the  same  time  blowing  over  the  plain  toward  the 
Alps.  Below,  the  wind  is  hot  enough  to  keep  its  vapor  in  a 
perfectly  transparent  state ;  but  it  meets  the  mountains,  is  tilted 
up,  expanded,  and  chilled.  The  cold  of  the  higher  summits 
also  helps  the  chill.  The  consequence  is  that  the  vapor  is  pre- 
cipitated as  rain  or  snow,  thus  producing  bad  weather  upon 
the  heights,  while  the  plains  below,  flooded  with  the  same  air, 
enjoy  the  aspect  of  the  unclouded  summer  sun.  Clouds  blow- 
ing from  the  Alps  are  also  sometimes  dissolved  over  the  plains 
of  Lombardy. 

In  connection  with  the  formation  of  clouds  by  mountains, 
one  particularly  instructive  effect  may  be  here  noticed.  You 
frequently  see  a  streamer  of  cloud  many  hundred  yards  in 
length  drawn  out  from  an  Alpine  peak.  Its  steadiness  appears 
perfect,  though  a  strong  wind  may  be  blowing  at  the  same  time 
over  the  mountain  head.  Why  is  the  cloud  not  blown  away  ? 
It  is  blown  away ;  its  permanence  is  only  apparent.  At  one 
end  it  is  incessantly  dissolved ;  at  the  other  end  it  is  incessantly 
renewed:  supply  and  consumption  being  thus  equalized,  the 
cloud  appears  as  changeless  as  the  mountain  to  which  it  seems 
to  cling.  When  the  red  sun  of  the  evening  shines  upon  these 
cloud-streamers  they  resemble  vast  torches  with  their  flames 
blown  through  the  air. 

ARCHITECTURE  OF  SNOW 

We  now  resemble  persons  who  have  climbed  a  difficult 
peak,  and  thereby  earned  the  enjoyment  of  a  wide  prospect. 
Having  made  ourselves  masters  of  the  conditions  necessary  to 
the  production  of  mountain  snow,  we  are  able  to  take  a  compre- 
hensive and  intelligent  view  of  the  phenomena  of  glaciers. 

A  few  words  are  still  necessary  as  to  the  formation  of  snow. 


278  ACHIEVEMENTS  IN  SCIENCE 

The  molecules  and  atoms  of  all  substances,  when  allowed  free 
play,  build  themselves  into  definite  and,  for  the  most  part, 
beautiful  forms  called  crystals.  Iron,  copper,  gold,  silve"  lead, 
sulphur,  when  melted  and  permitted  to  cool  gradually,  all  show 
this  crystallizing  power.  The  metal  bismuth  shows  it  in  a  par- 
ticularly striking  manner,  and  when  properly  fused  and  solidi- 
fied, self-built  crystals  of  great  size  and  beauty  are  formed  of 
this  metal. 

If  you  dissolve  saltpetre  in  water,  and  allow  the  solution  to 
evaporate  slowly,  you  may  obtain  large  crystals,  for  no  portion 
of  the  salt  is  converted  into  vapor.  The  water  of  our  atmos- 
phere is  fresh  though  it  is  derived  from  the  salt  sea.  Sugar 
dissolved  in  water,  and  permitted  to  evaporate,  yields  crystals 
of  sugar-candy.  Alum  readily  crystallizes  in  the  same  way. 
Flints  dissolved,  as  they  sometimes  are  in  nature,  and  per- 
mitted to  crystallize,  yield  the  prisms  and  pyramids  of  rock 
crystal.  Chalk  dissolved  and  crystallized  yields  Iceland  spar. 
The  diamond  is  crystallized  carbon.  All  our  precious  stones, 
the  ruby,  sapphire,  beryl,  topaz,  emerald,  are  all  examples  of 
this  crystallizing  power. 

You  have  heard  of  the  force  of  gravitation,  and  you  know  that 
it  consists  of  an  attraction  of  every  particle  of  matter  for  every 
other  particle.  You  know  that  planets  and  moons  are  held  in 
their  orbits  by  this  attraction.  But  gravitation  is  a  very  simple 
affair  compared  to  the  force,  or  rather  forces,  of  crystallization. 
For  here  the  ultimate  particles  of  mattter,  inconceivably  small 
as  they  are,  show  themselves  possessed  of  attractive  and  repel- 
lent poles,  by  the  mutual  action  of  which  the  shape  and  struct- 
ure of  the  crystal  are  determined.  In  the  solid  condition  the  at- 
tracting poles  are  rigidly  locked  together ;  but  if  sufficient  heat 
be  applied  the  bond  of  union  is  dissolved,  and  in  the  state  of 
fusion  the  poles  are  pushed  so  far  asunder  as  to  be  practically 
out  of  each  other's  range.  The  natural  tendency  of  the  mole- 
cules to  build  themselves  together  is  thus  neutralized. 

This  is  the  case  with  water,  which  as  a  liquid  is  to  all  ap- 
pearance formless.  When  sufficiently  cooled  the  molecules  are 
brought  within  the  play  of  the  crystallizing  force,  and  they 
then  arrange  themselves  in  forms  of  indescribable  beauty. 


PHYSICAL   GEOGRAPHY  279 

When  snow  is  produced  in  calm  air,  the  icy  particles  build 
themselves  into  beautiful  stellar  shapes,  each  star  possessing 
six  rays.  There  is  no  deviation  from  this  type,  though  in  other 
respects  the  appearances  of  the  snow-stars  are  infinitely  vari- 
ous. In  the  polar  regions  these  exquisite  forms  were  observed 
by  Dr.  Scoresby,  who  gave  numerous  drawings  of  them.  I 
have  observed  them  in  mid-winter  filling  the  air,  and  loading 
the  slopes  of  the  Alps.  But  in  England  they  are  also  to  be 
seen,  and  all  words  of  mine  must  fail  to  convey  an  impression 
of  their  vivid  beauty. 

It  is  worth  pausing  to  think  what  wonderful  work  is  going 
on  in  the  atmosphere  during  the  formation  and  descent  of 
every  snow-shower ;  what  building  power  is  brought  into  play ! 
and  how  imperfect  seem  the  productions  of  human  minds  and 
hands  when  compared  with  those  formed  by  the  blind  forces  of 
nature ! 

But  who  ventures  to  call  the  forces  of  nature  blind  ?  In 
reality,  when  we  speak  thus  we  are  describing  our  own  condi- 
tion. The  blindness  is  ours ;  and  what  we  really  ought  to  say, 
and  to  confess,  is  that  our  powers  are  absolutely  unable  to  com- 
prehend either  the  origin  or  the  end  of  the  operations  of  nature. 

But  while  we  thus  acknowledge  our  limits,  there  is  also 
reason  for  wonder  at  the  extent  to  which  science  has  mastered 
the  system  of  nature.  From  age  to  age,  and  from  generation 
to  generation,  fact  has  been  added  to  fact,  and  law  to  law,  the 
true  method  and  order  of  the  Universe  being  thereby  more  and 
more  revealed.  In  doing  this  science  has  encountered  and 
overthrown  various  forms  of  superstition  and  deceit,  of  credulity 
and  imposture.  But  the  world  continually  produces  weak  per- 
sons and  wicked  persons ;  and  as  long  as  they  continue  to  exist 
side  by  side,  as  they  do  in  this  our  day,  very  debasing  beliefs 
will  also  continue  to  infest  the  world. 

ATOMIC  POLES 

"  What  did  I  mean  when,  a  few  moments  ago  I  spoke  of 
attracting  and  repellent  poles  ? "  Let  me  try  to  answer  this 
question.  You  know  that  astronomers  and  geographers  speak 


280  ACHIEVEMENTS  IN  SCIENCE 

of  the  earth's  poles,  and  you  have  also  heard  of  magnetic  poles, 
the  poles  of  a  magnet  being  the  points  at  which  the  attraction 
and  repulsion  of  the  magnet  are  as  it  were  concentrated. 

Every  magnet  possesses  two  such  poles ;  and  if  iron  filings 
be  scattered  over  a  magnet,  each  particle  becomes  also  endowed 
with  two  poles.  Suppose  such  particles  devoid  of  weight  and 
floating  in  our  atmosphere,  what  must  occur  when  they  come 
near  each  other  ?  Manifestly  the  repellent  poles  will  retreat 
from  each  other,  while  the  attractive  poles  will  approach  and 
finally  lock  themselves  together.  And  supposing  the  particles, 
instead  of  a  single  pair,  to  possess  several  pairs  of  poles  arranged 
at  definite  points  over  their  surfaces;  you  can  then  picture 
them,  in  obedience  to  their  mutual  attractions  and  repulsions, 
building  themselves  together  to  form  masses  of  definite  shape 
and  structure. 

Imagine  the  molecules  of  water  in  calm  cold  air  to  be  gifted 
with  poles  of  this  description,  which  compel  the  particles  to  lay 
themselves  together  in  a  definite  order,  and  you  have  before 
your  mind's  eye  the  unseen  architecture  which  finally  produces 
the  visible  and  beautiful  crystals  of  the  snow.  Thus  our  first 
notions  and  conceptions  of  poles  are  obtained  from  the  sight  of 
our  eyes  in  looking  at  the  effects  of  magnetism ;  and  we  then 
transfer  these  notions  and  conceptions  to  particles  which  no 
eye  has  ever  seen.  The  power  by  which  we  thus  picture  to 
ourselves  effects  beyond  the  range  of  the  senses  is  what  philoso- 
phers call  the  Imagination,  and  in  the  effort  of  the  mind  to 
seize  upon  the  unseen  architecture  of  crystals,  we  have  an  ex- 
ample of  the  "  scientific  use  "  of  this  faculty.  Without  imagina- 
tion we  might  have  critical  power,  but  not  creative  power  in 
science. 

ARCHITECTURE  OF  LAKE  ICE 

We  have  thus  made  ourselves  acquainted  with  the  beautiful 
snow-flowers  self-constructed  by  the  molecules  of  water  in  calm, 
cold  air.  Do  the  molecules  show  this  architectural  power  when 
ordinary  water  is  frozen  ?  What,  for  example,  is  the  structure 
of  the  ice  over  which  we  skate  in  winter  ?  Quite  as  wonderful 
as  the  flowers  of  the  snow.  The  observation  is  rare,  if  not 


PHYSICAL   GEOGRAPHY  281 

new,  but  I  have  seen  in  water  slowly  freezing  six-rayed  ice- 
stars  formed,  and  floating  free  on  the  surface.  A  six-rayed 
star,  moreover,  is  typical  of  the  construction  of  all  our  lake  ice. 
It  is  built  up  of  such  forms  wonderfully  interlaced. 

Take  a  slab  of  lake  ice  and  place  it  in  the  path  of  a  concen- 
trated sunbeam.  Watch  the  track  of  the  beam  through  the 
ice.  Part  of  the  beam  is  stopped,  part  of  it  goes  through ;  the 
former  produces  internal  liquefaction ;  the  latter  has  no  effect 
whatever  upon  the  ice.  But  the  liquefaction  is  not  uniformly 
diffused.  From  separate  spots  of  the  ice  little  shining  points 
are  seen  to  sparkle  forth.  Every  one  of  those  points  is  sur- 
rounded by  a  beautiful  liquid  flower  with  six  petals. 

lee  and  water  are  so  optically  alike  that  unless  the  light 
falls  properly  upon  these  flowers  you  cannot  see  them.  But 
what  is  the  central  spot  ?  A  vacuum.  Ice  swims  on  water  be- 
cause, bulk  for  bulk,  it  is  ligher  than  water ;  so  that  when  ice 
is  melted  it  shrinks  in  size.  Can  the  liquid  flowers  then  occupy 
the  whole  space  of  the  ice  melted  ?  Plainly  no.  A  little  empty 
space  is  formed  with  the  flowers,  and  this  space,  or  rather  its 
surface,  shines  in  the  sun  with  the  luster  of  burnished  silver. 

In  all  cases  the  flowers  are  formed  parallel  to  the  surface  of 
freezing.  They  are  formed  when  the  sun  shines  upon  the  ice 
of  every  lake ;  sometimes  in  myriads,  and  so  small  as  to  require 
a  magnifying  glass  to  see  them.  They  are  always  attainable, 
but  their  beauty  is  often  marred  by  internal  defects  of  the  ice. 
Every  one  portion  of  the  same  piece  of  ice  may  show  them  ex- 
quisitely, while  a  second  portion  shows  them  imperfectly. 

Here  we  have  a  reversal  of  the  process  of  crystallization. 
The  searching  solar  beam  is  delicate  enough  to  take  the  mole- 
ules  down  without  deranging  the  order  of  their  architecture. 
Try  the  experiment  for  yourself  with  a  pocket-lens  on  a  sunny 
"  y.  You  will  not  fkid  the  flowers  confused ;  they  all  lie  paral- 
el  to  the  surface  of  freezing.  In  this  exquisite  way  every  bit 
of  the  ice  over  which  our  skaters  glide  in  winter  is  put  together. 

I  said  that  a  portion  of  the  sunbeam  was  stopped  by  the  ice 
and  liquefied  it.  What  is  this  portion  ?  The  dark  heat  of  the 
sun.  The  great  body  of  the  light  waves,  and  even  a  portion  of 
.e  dark  ones,  pass  through  the  ice  without  losing  any  of  their 


282  ACHIEVEMENTS  IN  SCIENCE 

heating  power.  When  properly  concentrated  on  combustible 
bodies,  even  after  having  passed  through  the  ice,  their  burning 
power  becomes  manifest. 

And  the  ice  itself  may  be  employed  to  concentrate  them. 
With  an  ice-lens  in  the  polar  regions  Dr.  Scoresby  has  often 
concentrated  the  sun's  rays  so  as  to  make  them  burn  wood,  fire 
gunpowder,  and  melt  lead ;  thus  proving  that  the  heating  power 
is  retained  by  the  rays,  even  after  they  have  passed  through  so 
cold  a  substance. 

By  rendering  the  rays  of  the  electric  lamp  parallel,  and  then 
sending  them  through  a  lens  of  ice,  we  obtain  all  the  effects 
which  Dr.  Scoresby  obtained  with  the  rays  of  the  sun. 


PHYSICAL  GEOGRAPHY 


Tides 

By  ELISHA  GRAY 

ANY  one  who  has  spent  a  summer  at  the  seashore  has 
observed  that  the  water  level  of  the  ocean  changes  twice 
in  about  twenty-four  hours,  or  perhaps  it  would  be  a  better 
statement  to  say  that  it  is  continually  changing,  and  that  twice 
in  twenty-four  hours  there  is  a  point  when  it  reaches  its  highest 
level  and  another  when  it  reaches  its  lowest.  It  swings  back 
id  forth  like  a  pendulum,  making  a  complete  oscillation  once 
twelve  hours.  When  we  come  to  study  this  phenomenon 
closely  we  find  that  it  varies  each  day,  and  that  for  a  certain 
iriod  of  time  the  water  will  reach  a  higher  level  each  succeed- 
ing day  until  it  culminates  in  a  maximum  height,  when  it  be- 
gins to  gradually  diminish  from  day  to  day  until  it  has  reached 
minimum.  Here  it  turns  and  goes  over  the  same  round 
again.  It  will  be  further  observed  that  the  time  occupied  be- 
tween one  high  tide  and  the  next  one  is  a  trifle  over  twelve 
hours.  That  is  to  say,  the  two  ebbs  and  flows  that  occur  each 
day  require  a  little  more  than  twenty-four  hours,  so  that  the 
tidal  day  is  a  little  longer  than  the  solar  day.  It  corresponds 
to  what  we  call  the  lunar  day. 

The  moon  goes  through  all  its  phases  once  in  twenty-eight 
lys.  The  tide  considered  in  its  simplest  aspect  is  a  struggle 
on  the  part  of  the  water  to  follow'the  moon.  There  is  a  mutual 
attraction  of  gravitation  between  the  earth  and  the  moon.  Be- 
cause the  water  of  the  earth  is  mobile  it  tends  to  pile  up  at  a 
point  nearest  the  moon.  But  the  earth  as  a  whole  also  moves 
toward  the  moon,  and  more  than  the  water  does,  keeping  its 

283 


284  ACHIEVEMENTS  IN  SCIENCE 

round  shape,  while  its  movable  water  (practically  enveloping  it) 
is  piled  up  before  it  toward  the  moon  and  left  accumulated  be- 
hind it  away  from  the  moon.  So  that  in  a  rough  way  it  is  a 
solid  round  earth,  surrounded  by  an  oval  body  of  water :  the 
long  axis  of  the  oval  representing  the  high  tides,  which,  as  they 
follow  the  moon,  slide  completely  around  the  earth  once  in 
every  twenty-four  hours.  Thus,  there  are  really  two  high  tides 
and  two  low  tides  moving  around  the  earth  at  the  same  time ; 
and  this  accounts  for  the  two  daily  tides. 

We  have  accounted  for  the  time  when  they  occur  in  the 
fact  that  the  water  attempts  to  follow  the  moon,  but  this  does 
not  account  for  the  gradual  changes  in  the  amount  of  fluctua- 
tion from  day  to  day.  The  problem  is  complicated  by  the  fact 
that  the  sun  also  has  an  attraction  for  the  earth  as  well  as  the 
moon.  But  from  the  fact  that  the  sun  is  something  like  four 
hundred  times  farther  from  the  earth  than  the  moon  is,  and 
also  the  fact  that  the  attraction  of  one  body  for  another  varies 
inversely  as  the  square  of  the  distance,  the  moon  has  an  im- 
mense advantage  over  the  sun,  although  so  much  smaller.  If 
the  power  of  the  moon  were  entirely  suspended,  or  if  the  moon 
were  blotted  out  of  existence,  there  would  still  be  a  tide.  The 
fluctuation  between  high  and  low  tide  would  not  be  nearly  so 
great  as  it  is  at  present,  but  it  would  occur  at  the  same  time 
each  day,  because  it  would  be  wholly  a  product  of  the  sun. 

It  will  be  easily  seen  that  these  two  forces  acting  upon  the 
water  at  the  same  time  will  cause  a  complicated  condition  in 
the  movement  of  the  waters  of  the  ocean.  There  will  come  a 
time  once  in  twenty-eight  days  when  the  sun  and  the  moon  will 
act  conjointly,  and  both  will  pull  in  the  same  direction  at  the 
same  time  upon  the  water.  This  joint  action  of  the  sun  and 
moon  produces  the  highest  tide,  which  is  called  the  "  spring  " 
tide.  From  this  point,  however,  the  tides  will  grow  less  each 
day,  because  the  relation  of  the  sun  and  moon  is  constantly 
changing,  owing  to  the  fact  that  it  requires  three  hundred  and 
sixty-five  days  for  the  sun  to  complete  his  apparent  revolution 
around  the  earth,  while  the  moon  does  her  actual  course  in 
twenty-eight  days.  When  the  sun  and  moon  have  changed 
their  relative  positions  so  that  they  are  at  right  angles  to  each 


PHYSICAL   GEOGRAPHY  285 

other  with  reference  to  the  earth — at  a  quarter-circle  apart— 
the  sun  and  moon  will  be  pulling  against  each  other ;  at  least 
this  is  the  point  where  the  moon  is  at  the  greatest  disadvantage 
with  reference  to  its  ability  to  attract  the  water. 

Because  one-quarter  around  the  earth  the  sun  is  creating 
his  own  tide,  which  to  that  extent  counteracts  the  effect  pro- 
duced by  the  moon,  the  tide  under  the  moon  at  this  point  is  at 
its  lowest  point  and  is  called  the  "neap"  tide.  When  the 
moon  has  passed  on  around  the  earth  to  a  point  where  it  is 
opposite  to  that  of  the  sun — at  a  half -circle  apart — there  will 
be  another  spring  tide,  and  then  another  neap  tide  when  it  is 
on  the  last  quarter,  and  from  that  point  the  tide  will  increase 
daily  until  it  reaches  the  point  where  the  sun  and  moon  are  in 
exact  line  with  reference  to  the  earth's  center,  when  another 
spring  tide  occurs.  From  this  it  will  be  seen  that  there  are 
two  spring  tides  and  two  neap  tides  in  each  twenty-eight  days. 
This  is  the  fundamental  law  governing  tides. 

There  are  many  other  conditions  that  modify  tidal  effects. 
Neither  the  sun  nor  the  moon  is  always  at  the  same  distance 
from  the  earth,  so  that  there  will  be  a  variation,  at  times,  in 
high  and  low  tides.  For  instance,  it  will  happen  sometimes 
that  when  the  sun  and  moon  are  acting  conjointly  they  will 
both  be  at  their  nearest  point  to  the  earth,  and  when  this  is  the 
case  the  spring  tide  will  be  much  higher  than  usual. 

For  many  years  the  writer  has  observed  that  artesian  wells, 
made  by  deep  borings  of  small  diameter  into  the  earth  to  a 
water  supply,  have  a  daily  period  of  ebb  and  flow,  as  well  as  a 
neap  and  spring  tide,  the  same  as  the  tides  of  the  ocean,  except 
that  the  process  is  reversed.  The  time  of  greatest  flow  of  an 
artesian  well  will  occur  at  low  tide  in  the  ocean.  This  might 
be  accounted  for  from  the  fact  that  when  the  tide  is  at  its 
height  the  moon  is  also  pulling  upon  the  crust  of  the  earth, 
which  would  tend  to  take  the  pressure  off  the  sand  rock  which 
lies  one  or  two  thousand  feet  below  the  surface,  and  through 
which  the  flow  of  water  comes,  and  thus  slacken  the  flow. 
When  the  moon  is  in  position  for  low  tide,  the  crust  of  the 
earth  would  settle  back  and  thus  produce  a  greater  pressure 
upon  the  water-bearing  rock.  This  is  the  only  theory  that  has 


286  ACHIEVEMENTS  IN  SCIENCE 

suggested  itself  to  the  writer  that  would  seem  to  account  for 
these  phenomena. 

Looked  at  from  one  standpoint,  it  is  easy  to  account  for 
tidal  action.  But  when  we  attempt  to  make  up  a  table  giving 
the  hour  and  minute  as  well  as  the  height  of  the  tide  at  that 
particular  time  we  find  that  we  have  a  very  complicated  mathe- 
matical problem.  Tables  are  made  out,  however,  so  that  we 
know  at  just  what  time  in  the  day  a  tide  will  occur  every  day 
in  the  year. 


PHYSICAL  GEOGRAPHY 


Why  Ice  Floats 

By  ELISHA  GRAY 

N'ATURE  is  full  of  surprises.     By  a  long  series  of  experi- 
mental investigations  you  think  you  have  established  a 
law  that  is  as  unalterable  as  those  of  the  Medes  and  Persians. 
But  once  in  a  while  you  stumble  upon  phenomena  that  seem 
to  contradict  all  that  has  gone  before. 

These,  however,  may  be  only  the  exceptions  that  prove  the 
rule.  It  is  recognized  as  a  fundamental  law  that  heat  expands 
and  cold  contracts ;  that  the  atom  when  in  a  state  of  intense 
motion  (which  is  the  condition  producing  the  effect  that  we 
call  "heat")  requires  more  room  than  when  its  motions  are  of 
a  less  amplitude.  In  other  words,  an  increase  in  the  amplitude 
of  atomic  motion  is  heating,  while  a  decrease  is  cooling.  It 
follows  from  the  above  statement  that  the  colder  a  body  be- 
comes the  smaller  will  be  its  dimensions.  There  are  two  or 
three,  and  perhaps  more,  exceptions  to  this  rule,  and  the  most 
notable  one  is  that  of  water.  Water  follows  the  same  law  that 
all  other  substances  do  under  the  action  of  heat  and  cold,  within 
certain  limits  only.  If  we  take  water,  say  at  fifty  degrees 
Fahrenheit  and  subject  it  to  cold  it  will  gradually  contract  in 
bulk  until  it  reaches  thirty-nine  degrees  Fahrenheit.  At  this 
point,  very  curiously,  contraction  ceases,  and  here  we  find  the 
maximum  density  of  water.  If  the  temperature  is  still  lowered 
we  find  the  bulk  is  gradually  increasing  instead  of  diminishing 
(as  is  the  rule  with  other  fluids),  and  when  it  reaches  the  freez- 
ing point  there  is  a  sudden  and  marked  expansion,  so  much  so 
that  a  cubic  foot  of  ice,  which  is  solidified  water,  will  not  weigh 

287 


288  ACHIEVEMENTS  IN  SCIENCE 

as  much  as  a  cubic  foot  of  water  before  it  freezes — hence  it 
floats. 

Let  us  try  an  experiment.  Take  a  small  glass  flask,  ter- 
minating in  a  long  neck,  say  of  four  to  six  inches,  and  of  small 
diameter.  Suppose  the  water  in  the  glass  to  be  at  fifty  degrees 
Fahrenheit.  Fill  the  flask  with  water  until  it  stands  halfway 
up  the  neck  at  fifty  degrees  temperature.  Now  immerse  the 
flask  gradually  in  hot  water,  and  observe  the  effect.  For  a 
moment  the  water  will  lower  in  the  neck  of  the  tube,  but  this 
is  due  to  the  fact  that  the  glass  expands  before  the  heat  is  com- 
municated to  the  water  and  enlarges  its  capacity.  But  immedi- 
ately the  water  will  begin  to  rise  as  the  heat  is  communicated 
to  it,  and  will  continue  to  expand  up  to  the  boiling  point.  Now 
take  the  flask  out  of  the  hot  water  and  gradually  introduce  it 
into  a  freezing  mixture  made  of  broken  ice  and  salt.  Immedi- 
ately the  water  will  begin  to  fall  in  the  tube,  showing  that  it  is 
contracting  under  the  cold,  and  it  will  continue  to  contract 
until  it  reaches  a  temperature  of  thirty-nine  degrees  Fahren- 
heit, when  it  will  come  to  a  standstill  and  then  proceed  to  ex- 
pand as  the  temperature  of  the  water  lowers.  When  it  reaches 
the  freezing  point  the  fluid  can  no  longer  rise  in  the  neck  of 
the  flask,  which  is  broken  by  the  sudden  expansion  that  takes 
place  at  this  point. 

To  show  what  an  irresistible  power  resides  in  the  atoms  of 
which  the  body  is  made,  let  us  take  an  iron  flask  with  walls  one- 
half  inch  or  more  in  thickness ;  fill  it  with  water  and  seal  it  up 
by  screwing  on  the  neck  an  iron  cap ;  now  plunge  it  into  the 
freezing  mixture,  and  the  first  effect  will  be  to  contract  the 
water  unless  it  is  already  below  thirty-nine  degrees  Fahrenheit, 
but  when  it  reaches  that  point  expansion  sets  in,  and  this  con- 
tinues to  the  freezing  point,  when  a  greatly  increased  expansion 
takes  place  suddenly.  The  walls  of  the  iron  flask,  although  a 
half -inch  in  thickness,  are  no  longer  able  to  resist  the  combined 
efforts  of  the  billions  upon  billions  of  the  atoms  of  which  the 
water  is  made  up,  in  their  individual  clamor  for  more  room, 
hence  the  flask  is  shivered  into  pieces. 

There  are  one  or  two  other  substances  which  are  exceptions 
to  the  general  rule,  but  we  will  mention  only  one,  which  is  the 


PHYSICAL   GEOGRAPHY  289 

metal  bismuth.  If  we  should  melt  a  sufficient  amount  to  fill 
an  iron  flask  such  as  we  have  described,  and  subject  it  to  the 
same  freezing  process,  the  flask  will  be  broken  the  same  as  in 
the  experiment  made  with  the  water. 

A  query  arises,  Why  this  phenomenon  ?  Why  does  water, 
in  cooling,  follow  a  different  law  from  that  of  nearly  all  other 
substances  ? 

This  is  a  case  where  it  is  much  easier  to  ask  a  question 
than  to  answer  it.  When  water  solidifies  at  the  moment  of 
freezing,  crystallization  sets  in.  But  what  is  crystallization? 
Crystallization  is  a  peculiar  arrangement  of  the  molecules  of 
matter,  which  takes  place  in  some  substances  when  they  pass 
from  the  liquid  to  the  solid  form.  The  molecules  assume  defi- 
nite forms  and  shapes,  according  to  the  nature  of  the  substance. 
When  water  assumes  the  solid  form  under  the  action  of  cold 
the  molecules  arrange  themselves  according  to  certain  definite 
and  fixed  laws,  the  result  of  which  is  to  increase  the  bulk  to  a 
considerable  extent  over  that  which  the  same  number  of  mole- 
cules would  occupy  at  a  temperature  of  thirty-nine  degrees 
Fahrenheit.  Hence,  as  has  been  heretofore  stated,  a  given 
block  of  solidified  water  is  lighter  than  the  same  bulk  would 
be-in  the  fluid  state,  and  this  is  the  reason  why  ice  floats. 

What  would  happen  in  case  nature  did  not  make  this  excep- 
tion to  the  laws  of  expansion  and  contraction  by  heat  and  cold, 
in  the  case  of  water  ?  First,  our  lakes  would  freeze  from  the 
bottom  upward ;  as  soon  as  the  surface  became  frozen,  or  even 
colder  than  the  water  underneath,  it  would  drop  to  the  bottom, 
the  warmer  water  below  coming  up  by  a  well-known  law — that 
the  warmer  fluid  rises  and  the  colder  falls.  This  circulation 
would  continue  until  ice  began  to  form,  which  would  immedi- 
ately drop  to  the  bottom,  and  this  process  would  go  on  until  the 
whole  mass  were  frozen  solid.  In  the  same  way  our  rivers  in 
the  northern  climates  would  freeze  from  the  bottom,  and  in 
time  our  valleys  would  fill  up  with  ice  to  a  thickness  that  the 
summer's  sun  would  never  melt,  and  gradually  all  north  of  a 
certain  zone  would  become  a  great  glacier,  rendering  not  only 
the  lakes  and  rivers,  but  also  the  surface  of  the  earth,  unfitted 
for  animal  life. 
19 


PHYSICAL  GEOGRAPHY 


Franklin's  Kite  Modernized 

By  ALEXANDER  McADIE 

recent  improvements  in  kites  have  suggested  perhaps 
to  many  the  question,  "How  would  Franklin  perform 
his  kite  experiment  to-day  ? "  It  may  seem  a  little  presumptu- 
ous to  speak  for  that  unique  philosopher,  and  attempt  to  outline 
the  modifications  he  would  introduce  were  he  to  walk  on  earth 
again  and  fly  kites  as  of  yore ;  for,  with  the  exception  of  Jeffer- 
son, perhaps  his  was  the  most  far-seeing  and  ingenious  mind  of 
a  remarkable  age.  But  the  world  moves;  and  in  making  kites, 
as  well  as  in  devising  electrometers  and  apparatus  for  measur- 
ing the  electricity  of  the  air,  great  advances  have  been  made. 
Franklin  would  enjoy  repeating  his  kite  experiment  to-day, 
using  modern  apparatus.  What  changes  and  lines  of  investi- 
gation he  would  suggest  are  beyond  conjecture. 

A  hundred  and  fifty  years  ago  a  ragged  colonial  regiment 
drew  up  before  the  home  of  its  philosopher-colonel  and  fired  an 
ill-timed  salute  in  his  honor.  A  fragile  electrical  instrument 
was  shaken  from  a  shelf  and  shattered.  Franklin  doubtless  ap- 
preciated the  salute  and  regretted  the  accident.  In  the  course  of 
his  long  life  he  received  other  salutes,  as  when  the  French 
Academy  rose  at  his  entrance ;  and  he  constructed  and  worked 
with  other  electrometers ;  but  for  us  that  first  experience  will 
always  possess  a  peculiar  interest.  The  kite  and  the  electro- 
meter betray  the  intention  of  the  colonial  scientist  to  explore 
the  free  air,  and,  reaching  out  from  earth,  study  air  electrifica- 
tion in  situ.  He  made  the  beginning  by  identifying  the  light- 
ning flash  with  the  electricity  developed  by  the  frictional 

290 


PHYSICAL   GEOGRAPHY  291 

machine  of  that  time.  A  hundred  patient  philosophers  have 
carried  on  the  work,  improving  methods  and  apparatus,  until 
to-day  we  stand  upon  the  threshold  of  a  great  electrical  survey 
of  the  atmosphere.  It  is  no  idle  prophecy  to  say  that  the 
twentieth  century  will  witness  wonderful  achievements  in 
measuring  the  potential  of.  the  lightning  flash,  in  demonstrating 
the  nature  of  the  aurora,  and  in  utilizing  the  electrical  energy 
of  the  cloud.  The  improved  kite  and  air-runner  will  be  the 
agency  through  which  these  results  will  be  accomplished. 

The  famous  kite  experiment  is  described  by  Franklin  in  a 
letter  dated  October  19,  1752:  "Make  a  small  cross  of  light 
sticks  of  cedar,  the  arms  so  long  as  to  reach  to  the  four  corners 
of  a  large,  thin  silk  handkerchief  when  extended.  Tie  the  cor- 
ners of  the  handkerchief  to  the  extremities  of  the  cross,  so  you 
have  the  body  of  a  kite  which,  being  properly  accommodated 
with  a  tail,  loop,  and  string,  will  rise  in  the  air  like  those  made 
of  paper,  but  being  made  of  silk  is  better  fitted  to  bear  the  wet 
and  wind  of  a  thunder-gust  without  tearing.  To  the  top  of  the 
upright  stick  of  the  cross  is  to  be  fixed  a  very  sharp-pointed 
wire  rising  a  foot  or  more  above  the  wood.  To  the  end  of  the 
twine  next  the  hand  is  to  be  tied  a  silk  ribbon,  and  where  the 
silk  and  twine  join  a  key  may  be  fastened.  This  kite  is  to  be 
raised  when  a  thunder-gust  appears  to  be  coming  on,  and  the 
person  who  holds  the  string  must  stand  within  a  door  or  win- 
dow, or  under  some  cover,  so  that  the  silk  ribbon  may  not  be 
wet ;  and  care  must  be  taken  that  the  twine  does  not  touch  the 
frame  of  the  door  or  window.  As  soon  as  the  thunder-clouds 
come  over  the  kite,  the  pointed  wire  will  draw  the  electric  fire 
from  them,  and  the  kite,  with  all  the  twine,  will  be  electrified, 
and  stand  out  every  way  and  be  attracted  by  an  approaching 
finger.  And  when  the  rain  has  wet  the  kite  and  twine  you 
will  find  the  electric  fire  stream  out  plentifully  from  the  key  on 
the  approach  of  your  knuckle." 

Now,  how  would  we  perform  this  experiment  „  to-day  and 
with  what  results  ?  Having  flown  big  kites  during  thunder- 
storms, it  may  perhaps  be  best  to  describe  step  by  step  two  of 
these  experiments,  and  then  speak  of  what  we  know  can  be 
done,  but  as  yet  has  not  been  done. 


292  ACHIEVEMENTS  IN  SCIENCE 

Our  first  repetition  of  Franklin's  kite  experiment  was  at 
Blue  Hill  Observatory,  some  ten  miles  southwest  of  Boston, 
one  hundred  and  thirty-three  years  after  its  first  trial.  There 
were  two  large  kites  silk-covered  and  tin-foiled  on  the  front 
face.  These  kites  were  of  the  ordinary  hexagonal  shape,  for  in 
1885  Malay  and  Hargrave  kites  were  all  unknown  to  us.  Fif- 
teen hundred  feet  of  strong  hemp  fish-line  were  wrapped  loosely 
with  uncovered  copper  wire  of  the  smallest  diameter  suitable, 
and  this  was  brought  into  a  window  on  the  east  side  of  the 
observatory,  through  rubber  tubing  and  blocks  of  paraffin. 
Pieces  of  thoroughly  clean  plate  glass  were  also  used.  Mate- 
rials capable  of  giving  a  high  insulation  were  not  so  easily  had 
then  as  now.  We  knew  very  little  about  mica;  and  quartz 
fibers  and  Mascart  insulators  could  not  be  obtained  in  the 
United  States.  Our  electrometer,  however,  was  a  great  im- 
provement upon  any  previous  type,  and  far  removed  from  the 
simple  pith-ball  device  used  by  Franklin.  Knowing  that  an 
electrified  body  free  to  move  between  two  other  electrified  bodies 
will  always  move  from  the  higher  to  the  lower  potential,  Lord 
Kelvin  devised  an  instrument  consisting  of  four  metallic  sec- 
tions, symmetrically  grouped  around  a  common  center  and  in- 
closing a  flat  free-swinging  piece  of  aluminum  called  a  needle. 
The  end  of  the  kite  wire  is  connected  with  the  needle  and  the 
sections  or  quadrants  are  alternately  connected  and  then  elec- 
trified, one  set  with  a  high  positive  potential,  say  five  hundred 
volts,  and  the  other  with  a  corresponding  negative  value,  say 
five  hundred  volts  lower  than  the  ground. 

Perhaps  the  most  noteworthy  result  of  these  earlier  experi- 
ments was  the  discovery  (for  such  we  think  it  was)  that  showery 
or  thunder-storm  weather  was  not  the  only  condition  giving 
marked  electrical  effects.  The  electrometer  needle  would  be 
violently  deflected  and  large  sparks  obtained  at  other  times. 
Day  after  day  as  we  flew  the  kite  we  found  this  high  electrifi- 
cation of  the  air,  and  we  had  no  trouble  in  getting  sparks  even 
when  the  sky  was  cloudless.  One  other  discovery  was  made, 
and  this  would  have  delighted  Franklin  more  than  the  other, 
for  he  was  always  most  pleased  when  a  practical  application 
was  in  sight.  Seated  within  the  instrument  room  of  the  ob- 


PHYSICAL   GEOGRAPHY  293 

servatory,  with  his  back  to  the  open  window  through  which 
came  the  kite  wire  carefully  insulated,  and  the  kite  high  in  air, 
the  observer  closely  watching  the  index  of  the  electrometer 
could  tell  positively,  and  as  quickly  as  one  outside  watching  the 
kite,  whether  it  rose  or  fell.  When  the  kite  rose,  up  went  the 
voltage,  and  vice  versa.  In  other  words,  the  electric  potential 
of  the  air  increased  with  elevation.  It  must  be  confessed  that 
the  kites  made  to-day  would  have  behaved  better  and  flown 
with  more  steadiness  than  the  one  we  used.  It  may  have  been 
the  varying  wind,  or  more  likely  wrong  proportions  in  the  kite 
and  tail;  but  our  old  hexagonal  kite  would  dive  even  when 
high  in  air.  Once  we  kept  the  kite  aloft  from  the  forenoon 
until  late  at  night,  but  that  was  something  unusual. 

Passing  now  over  six  years  in  which  we  had  been  busy 
measuring  the  electrification  of  the  air  under  all  conditions,  and 
discovering,  for  example,  that  a  snow-storm  was  almost  identical 
with  a  thunder-storm  in  its  tremendous  electrical  changes,  we 
come  to  the  year  1891,  when  we  again  flew  kites  for  the  pur- 
pose of  electrically  exploring  the  air.  Our  experiments  at  the 
top  of  the  Washington  Monument  in  1885  and  1886  (especially 
those  during  severe  thunder-storms,  when  we  obtained  poten- 
tials as  high  as.  three  and  four  thousand  volts  just  before  the 
lightning),  had  given  us  an  insight  into  the  strains  and  stresses 
in  the  air,  and  taught  us  what  to  expect  at  such  times.  There 
was  still  little  improvement  in  the  kite,  but  much  better  elec- 
trical apparatus  was  at  hand.  It  may  seem  ridiculous,  but  we 
hauled  nearly  a  wagon-load  of  electrical  apparatus  to  the  sum- 
mit of  the  hill,  and  found  occasion  to  use  all  of  it.  Our  insula- 
tors were  delicate  glass  vessels,  curiously  shaped,  containing 
sulphuric  acid,  and  able  to  hold  with  little  leakage  the  highest 
known  potentials.  Besides  these  fine  Mascart  insulators,  we 
had  hundreds  of  distilled-water  batteries  and  two  electrometers, 
one  a  Mascart  quadrant,  the  other  a  large  multiple  quadrant. 
The  chief  aim  that  year  was  to  secure  by  mechanical  means 
(discarding  the  photographic  and  eye  methods)  a  continuous 
record  of  the  potential.  When  we  can  study  the  potential  at 
any  moment  and  still  have  a  record  of  it,  the  relation  of  the 
electricity  of  the  air  to  the  pressure,  temperature,  and  moisture 


294  ACHIEVEMENTS  IN  SCIENCE 

will  be  more  easily  investigated.  Among  our  records  that  year 
there  is  one  date,  June  30,  1891,  where  a  direct  comparison  of 
the  electrification  of  the  air  fifteen  or  twenty  feet  from  the 
ground  and  at  a  height  of  about  five  hundred  feet  is  shown. 
In  one,  the  potential  was  obtained  by  a  water-dropper  collector 
from  a  second-story  window  in  the  observatory,  and  in  the 
other  was  obtained  by  means  of  the  kite.  It  will  be  seen  how 
much  higher  the  kite  values  are,  although  the  kite  was  a  much 
slower  accumulator  of  electricity.  In  the  next  year,  1892,  the 
kite  was  flown  several  times  during  thunder-storms,  but  gener- 
ally during  afternoon  storms;  and  in  the  lull  preceding  the 
wind  rush  the  kite  would  fall.  It  was  not  until  August  9th 
that  we  succeeded  in  going  through  a  storm  with  the  kite  still 
flying.  About  1 1  A.M.  the  kite  was  sent  aloft,  and  it  remained 
aloft  until  after  10  P.M.  From  the  observatory  one  can  see  to 
the  west  fifty  or  more  miles,  and  a  thunder-storm  came  into 
view  just  about  sunset.  The  kite  was  flying  steadily,  and 
whenever  a  finger  was  held  near  the  kite-wire  there  was  a  per- 
fect fusillade  of  sparks.  As  the  darkness  increased,  the  polished 
metallic  and  glass  surfaces  in  the  large  electrometer  reflected 
the  sparks,  now  strong  enough  to  jump  across  the  air-gaps,  and 
the  incessant  sizzling  threatened  to  burn  out  the  instrument. 
The  vividness  of  the  lightning  in  the  west  also  made  it  plain 
that  the  storm  was  one  of  great  violence,  and  as  the  observa- 
tory itself  would  be  jeopardized,  one  of  the  four  men  present 
proposed  to  cut  the  wired  string  and  let  the  kite  go.  But  even 
that  was  easier  said  than  done,  for  to  touch  the  string  was  to 
receive  a  severe  shock.  It  was  necessary,  however,  to  get  out 
of  the  scrape,  and  one  of  the  party  took  the  kite-string  and 
broke  the  connection  with  the  electrometer  and  insulators. 
While  he  was  in  the  act  of  doing  this,  the  others,  who  by  this 
time  were  outside  the  building,  saw  a  flash  of  lightning  to  the 
west  of  the  hill.  The  observer  who  was  undoing  the  kite-wire 
did  not  see  this  flash.  He  saw  a  brilliant  flare-up  in  the  elec- 
trometer, and  at  the  same  instant  felt  a  severe  blow  across  both 
arms.  Notwithstanding,  he  loosened  the  wire,  and,  dropping 
an  end  without,  it  took  but  a  few  moments  to  make  it  fast  on 
the  hillside  some  distance  away  from  the  observatory.  There 


PHYSICAL   GEOGRAPHY  295 

it  remained  for  the  rest  of  the  night.  A  io5-volt  incandescent 
lamp  was  placed  between  the  end  of  the  kite-wire  and  a  wire 
running  to  the  ground.  There  was  some  light,  but  no  incan- 
descence of  the  filament.  It  was  more  in  the  nature  of  a  creep- 
ing of  the  charge  over  the  outer  glass  surface  of  the  lamp. 
Stinging  sparks  were  felt  whenever  the  kite-wire  was  touched. 
The  storm  gradually  passed  over,  the  lightning  being  vivid  and 
frequent  in  the  west  and  north,  and,  as  we  learned  next  day, 
doing  considerable  damage.  The  nearest  flash  to  the  hill,  how- 
ever, as  well  as  we  could  determine  by  the  interval  between 
thunder  and  flash,  was  4,500  feet  away,  so  that  the  discharge 
which  the  observer  felt  while  loosening  the  wire  must  have 
been  a  sympathetic  one.  We  obtained  a  photograph  of  the 
prime  discharge,  and  very  curiously  this  shows  a  remarkable 
change  of  direction. 

This  year,  in  some  interesting  experiments  made  on  the 
roof  of  the  Mills  Building  at  San  Francisco,  it  was  noticed  that 
the  roof,  which  has  a  covering  of  bitumen,  was  a  good  insulator. 
Ordinarily  one  may  touch  the  reel  on  which  the  kite-wire  is 
wound  without  being  shocked,  but  if  a  wire  be  connected  with 
the  ventilating  pipes  running  to  the  ground  there  are  small 
sparks.  Introducing  a  condenser  in  the  circuit,  the  intensity 
of  the  spark  is  increased.  It  only  remains  to  construct  an  ap- 
propriate coil  of  the  kite-wire  and  place  within  it  another  inde- 
pendent coil.  In  the  outer  coil  a  quick  circuit-breaker  may  be 
placed,  and  theoretically  at  least  we  shall  transform  down  the 
high  potential  and  low  amperage  charge  of  the  air  to  a  current 
of  less  potential  and  greater  amperage.  This  can  be  put  to 
work  and  the  long-delayed  realization  of  Franklin's  plan  of  har- 
nessing the  electricity  of  the  air  be  consummated.  It  may  not 
be  a  profitable  investment  from  the  commercial  standpoint,  but 
no  one  can  say  what  this  tapping  of  the  aerial  reservoir  may 
lead  to.  Determining  the  nature  and  origin  of  the  aurora  will 
be  as  great  a  scientific  achievement  as  utilizing  the  energy  of 
Niagara  Falls. 


CHEMISTRY 
The  Great  Problems  of  Chemistry 

By  ALFRED  RUSSEL  WALLACE 

r  I AHE  science  of  modern  chemistry  has  been  created  during 
JL  the  present  century,  but  its  phenomena  and  laws  are  so 
complex  that  it  presents  only  a  few  of  those  great  discoveries 
which  are  the  starting-points  for  new  developments,  and  which 
can  at  the  same  time  be  popularly  described.  The  most  im- 
portant of  all — that  which  constitutes  the  very  foundation  of 
chemistry  as  a  science — is  the  law  of  chemical  combination  in 
multiple  proportions,  together  with  the  atomic  theory  which 
serves  to  explain  it. 

The  fact  of  chemical  combination  in  definite  proportions 
was  suspected  by  some  of  the  older  chemists,  but  Dalton,  in 
the  early  years  of  this  century,  was  the  first  to  establish  it 
firmly  as  a  general  principle,  and  to  explain  it  by  means  of  a 
comparatively  simply  theory.  To  illustrate  by  examples,  it  is 
found  that  the  two  gases,  nitrogen  and  oxygen,  combine  to 
form  a  variety  of  compounds,  such  as  nitrous  oxide  or  "  laugh- 
ing gas,"  nitric  oxide,  and  several  others.  Nitrous  oxide,  or  in 
chemical  language,  nitrogen  monoxide,  consists  of  28  parts  by 
weight  of  nitrogen  to  16  of  oxygen,  and  all  the  other  com- 
pounds of  the  same  gases  consist  of  two,  three,  four,  or  five 
times  as  much  oxygen  to  the  same  quantity  of  nitrogen.  Water 
consists  of  1 6  parts  of  oxygen  to  2  of  hydrogen,  and  there  is 
another  compound  in  which  32  parts  of  oxygen  combine  with 
the  same  weight  of  hydrogen,  forming  hydrogen-dioxide  or  oxy- 
genated water.  This  law  applies  to  every  chemical  compound 
yet  discovered,  and  as  every  element  has  a  minimum  propor- 

296 


CHEMISTRY  297 

tionate  weight,  which  can  combine  with  any  other  element,  these 
are  called  the  atomic  or  combining  weights  of  the  elements.  As 
the  weight  of  the  hydrogen  in  all  its  combinations  is  much  less 
than  the  weight  of  the  element  it  combines  with,  this  gas  is 
taken  as  the  unit  of  measurement  of  atomic  weights.  Nitrogen 
is  thus  found  to  have  an  atomic  weight  of  14,  oxygen  16,  and 
chlorine  35.  These  are  all  gases;  but  many  solids  have  much 
lower  atomic  weights,  carbon  being  12,  and  the  rare  metal  be- 
ryllium only  9.  Of  other  metals,  that  of  aluminium  is  27,  cop- 
per 63,  iron  56,  silver  107,  tin  117,  and  gold  196.  There  is  thus 
no  constant  relation  between  atomic  weights  and  specific  gravi- 
ties. Tin  is  a  little  lighter  than  iron,  but  has  nearly  double  its 
atomic  weight ;  gold  has  a  high  atomic  weight,  but  bismuth  has 
a  higher  still,  although  only  half  its  specific  gravity. 

These  facts  are  elucidated,  and  to  some  extent  explained, 
by  the  atomic  theory  of  Dalton.  He  supposed  each  element 
to  consist  of  atoms,  an  atom  being  the  smallest  portion  that  has 
the  properties  of  the  element,  and  the  atom  of  each  element 
has  a  different  weight.  Hence,  when  one  element  combines 
with  another,  the  proportions  must  be  either  those  represented 
by  the  atomic  weights,  or  some  multiple  of  those  weights,  since 
the  atoms  are  assumed  to  be  indivisible.  This  wil!  be  made 
clearer  by  another  example.  The  atomic  weights  of  nitrogen 
and  oxygen  are  as  14  to  16,  and  these  elements  combine  in 
five  different  proportions,  as  shown  by  the  following,  each  let- 
ter representing  an  atom  of  the  element  of  which  it  is  the  initial 
letter. 

Chemical 
Symbol. 

N    N     O  =  Nitrogen  monoxide  N2O 

N    N     O     O  =  Nitrogen  dioxide      N2O2 

N     N     O     O     O  =  Nitrogen  trioxide     O2N3 

N    N     O     O     O     O  =  Nitrogen  tetroxide   N2O4 

NNOOOOO=  Nitrogen  pentoxide  N2O& 

The  atomic  or  combining  weights  of  all  the  elements  having 
been  carefully  determined  by  numerous  experiments,  a  beauti- 
ful system  of  chemical  symbols  has  been  formed  which  greatly 
facilitates  the  study  of  the  innumerable  complex  substances 
that  have  to  be  investigated.  Each  element  is  indicated  either 


298  ACHIEVEMENTS  IN  SCIENCE 

by  one  or  two  letters,  being  the  initial  letter,  or  some  two  char- 
acteristic letters,  of  its  chemical  name,  so  that  nearly  seventy 
elements  are  thus  clearly  defined.  But  these  symbols  repre- 
sent not  only  the  element,  but  a  definite  proportional  weight — 
the  atomic  weight.  Thus  H  means  a  unit  weight  of  hydrogen ; 
C  means  12  times  that  weight  of  carbon;  Fe  (ferrum)  means 
56  times  that  weight  of  iron.  Hence  the  symbol  for  any  com- 
pound substance  tells  us  in  the  most  compact  form  possible, 
not  only  the  elements  of  which  it  is  composed,  but  the  ex- 
act proportions  in  which  these  elements  are  combined.  Thus 
C2H6O  is  the  chemical  symbol  for  pure  alcohol,  showing  that 
it  is  a  compound  of  two  atoms  of  carbon,  six  of  hydrogen,  and 
one  of  oxygen.  Looking  now  at  a  table  of  atomic  weights,  we 
find  that  this  gives  us  24  carbon,  6  hydrogen,  and  16  oxygen 
in  each  46  parts  of  alcohol.  By  means  of  these  symbols  and 
the  accurate  determination  of  atomic  weights,  all  the  complex 
combinations  and  decompositions  that  occur  during  the  investi- 
gations of  the  chemist  can  be  represented  in  a  kind  of  chemical 
algebra,  and  the  peculiar  formulae  thus  obtained  often  suggest 
further  experiments  leading  to  new  discoveries. 

Almost  at  the  same  time  that  Dalton  was  working  at  his 
atomic  theory,  Davy  (afterward  Sir  Humphrey  Davy)  made  the 
remarkable  discovery  of  two  new  elements  by  decomposing 
soda  and  potash  by  means  of  an  electric  current,  resulting  in 
the  production  of  the  metals  sodium  and  potassium.  This 
placed  in  the  hands  of  chemists  a  powerful  agent  which  led  to 
the  discovery  of  other  elements,  though  in  this  respect  it  has 
been  surpassed  by  spectrum  analysis,  which  is  equally  effective 
in  the  domains  of  chemistry  and  astronomy. 

Among  the  more  interesting  discoveries  of  modern  chemis- 
try are  the  methods  of  liquefying  the  various  gases,  and  even 
solidifying  many  of  them ;  while  by  means  of  the  intense  heat 
of  the  electric  furnace  all  the  solid  elements  can  be  melted  and 
many  vaporized,  leading  to  the  conclusion  that  all  matter  can 
exist  in  the  three  states — solid,  liquid,  and  gaseous — according 
to  the  degree  of  heat  to  which  it  is  exposed. 

The  highly  complex  constitution  of  various  organic  pro- 
ducts— albumin,  fat,  gums,  resins,  acids,  oils,  ethers,  etc. — is  the 


CHEMISTRY  299 

subject  of  organic  chemistry,  the  study  of  which  has  led  to 
some  of  the  most  popularly  interesting  discoveries.  Coal-tar 
has  furnished  us  with  a  wonderful  series  of  coloring  matters, 
such  as  the  aniline  and  other  dyes,  while  from  the  same  mate- 
rial are  produced  benzol,  carbolic  acid,  naphtha,  creosote,  arti- 
ficial quinine,  and  saccharine,  a  substitute  for  sugar.  The  new 
explosives,  such  as  dynamite  and  nitro-glycerine,  are  produced 
from  animal  or  vegetable  fatty  matters ;  while  some  of  the 
greatest  triumphs  of  the  modern  chemist  are  the  artificial  pro- 
duction of  natural  substances,  which  were  long  supposed  to  be 
due  to  organic  processes  alone.  Such  are  the  dye  indigo,  citric 
acid,  urea,  and  some  others. 

The  most  recent  great  advance  in  the  philosophy  of  chemis- 
try is  exhibited  in  the  views  of  the  Russian  chemist,  Mendeleef, 
as  to  the  natural  arrangement  of  the  elements,  with  certain  de- 
ductions from  it.  The  whole  of  the  best-known  elements  form 
eight  groups,  placed  in  vertical  columns,  depending  on  certain 
similarities  in  their  powers  of  chemical  combination.  These 
are  further  arranged  in  twelve  horizontal  series,  in  which  the 
atomic  weights  are  most  nearly  alike,  while  increasing  regularly 
from  the  first  to  the  eighth  group.  In  the  table  thus  formed 
there  are  certain  gaps  in  the  regular  order  of  increased  atomic 
weights,  as  if  some  elements  were  wanting,  while  in  other  cases 
the  place  of  an  element  due  to  its  atomic  weight  did  not  accord 
with  that  dependent  on  its  chemical  properties.  But  the  gen- 
eral symmetry  of  the  whole  arrangement  was  such  that  Mende- 
leef predicted  the  future  discovery  of  elements  to  fill  the  gaps, 
and  named  the  chemical  and  physical  properties  of  these  un- 
known elements.  In  a  few  years  three  new  elements  were  dis- 
covered— gallium,  scandium,  and  germanium — and  they  pre- 
cisely filled  up  three  of  the  gaps  in  the  system.  Further  re- 
search as  to  the  atomic  weights  of  the  elements  that  did  not  fit 
into  the  scheme  showed  that  errors  had  been  made,  that  of 
uranium  being  much  too  low,  while  in  the  cases  of  gold,  tellu- 
rium, and  titanium  it  was  too  great.  The  remarkable  success 
of  these  predictions — a  success  always  considered  the  best 
proof  of  the  truth  of  a  theory — renders  it  almost  certain  that 
the  true  relations  of  the  elements  have  now  been  approximately 


300  ACHIEVEMENTS  IN  SCIENCE 

ascertained,  while  it  strengthens  the  belief  of  those  who  think 
that  what  we  term  elements  are  not  really  so,  but  that  their 
differences  depend  on  special  modes  of  aggregation  of  a  few 
simple  atoms,  whose  cohesion  is  so  strong  that  we  are  not  yet, 
and  perhaps  never  shall  be,  able  to  overcome  it. 

It  is  therefore  by  no  means  impossible,  perhaps  not  even 
improbable,  that  methods  will  be  discovered  of  either  breaking 
up  some  of  the  elements  and  producing  new  elements  which 
are  common  to  two  or  more  of  them,  or  of  solving  the  problem 
which  occupied  the  alchemists  of  the  Middle  Ages— the  trans- 
mutation of  some  of  the  inferior  metals  into  gold.  Within  the 
last  few  months  a  well-known  American  chemist  declared  that 
he  has  solved  the  problem  of  producing  gold  out  of  silver  at  a 
comparatively  small  cost,  and  that  when  he  had  made  a  few 
millions  by  his  process  he  would  make  it  known.  A  few  years 
ago  this  claim  would  have  been  scouted  as  that  of  a  dreamer, 
but  at  the  present  day  it  is  really  less  unexpected  than  was  the 
discovery  of  the  marvelous  powers  of  what  are  termed  the 
Rontgen  rays. 

It  will  thus  be  seen  that  chemistry,  as  a  science,  has  not 
furnished  discoveries  of  such  a  startling  nature  as  those  in  the 
domain  of  physics.  But  this  is  largely  due  to  the  fact  that  we 
have  already,  in  our  earlier  chapters,  dealt  with  the  more  popu- 
lar and  industrial  aspects  of  chemical  inventions.  Gas  illumina- 
tion, petroleum  oil-lamps,  lucifer  matches,  and  all  the  wonders 
of  photography  are  essentially  applications  of  chemistry ;  and 
the  last  of  these,  in  its  marvelous  results,  both  in  the  arts  and 
in  its  various  applications  to  astronomical  research,  is  not  sur- 
passed by  the  achievements  of  any  other  department  of  science. 


CHEMISTRY 
Ancient  and  Mediaeval  Chemistry 

By  M.   P.   E.   BERTHELOT 

/CHEMISTRY  is  a  modern  science,  constituted  hardly  a 
Vy  century  ago ;  but  its  theoretical  problems  were  discussed 
and  its  practices  put  in  operation  during  all  the  Middle  Ages. 
The  nations  of  antiquity  were  already  acquainted  with  them, 
and  their  origin  is  lost  in  the  night  of  primitive  religions  and 
prehistoric  civilizations.  I  have  described  elsewhere  the  first 
rational  attempts  to  explain  the  chemical  transformations  of 
matter,  and  purpose  now  to  speak  of  the  chemical  industries  of 
the  ancient  world,  and  their  transmission  to  the  Latins  of  the 
Middle  Ages.  The  story  is  of  interest  as  showing  how  the  cul- 
tivation of  the  sciences  has  been  perpetuated  in  the  material 
line  by  the  necessities  of  their  adaptations,  through  the  catas- 
trophes of  invasions  and  the  ruin  of  civilization.  Only  the 
total  extermination  of  populations,  such  as  was  at  times  prac- 
ticed by  the  Mongols  and  the  Tartars,  could  completely  destroy 
this  cultivation.  But  such  horrors  as  those  perpetrated  by 
Tamerlane  have  been  of  rare  occurrence. 

From  the  most  remote  times  man  has  applied  chemical 
operations  to  his  necessities,  performing  them  for  metallurgy, 
ceramics,  dyeing,  painting,  the  preservation  of  food,  medicine, 
and  the  art  of  war.  While  gold  and  sometimes  silver  and  cop- 
per existed  in  the  native  state,  and  required  only  mechanical 
preparation,  lead,  tin,  iron,  and  often  copper  and  silver,  had  to 
be  extracted  from  their  usual  minerals  by  very  complicated  arti- 
fices. The  production  of  alloys  necessary  for  the  fabrication 
of  arms,  money,  and  jewels  is  also  an  essentially  chemical  art. 

301 


302  ACHIEVEMENTS  IN  SCIENCE 

The  study  of  the  alloys  used  in  goldsmiths'  work  gave  rise  to 
the  prejudices  and  frauds  of  alchemy,  as  is  proved  by  the  testi- 
mony of  an  Egyptian  papyrus  preserved  in  the  Leyden  Mu- 
seum, and  of  the  writings  of  the  Grecian  alchemists. 

The  art  of  preparing  cement,  pottery,  and  glass,  likewise, 
depends  on  chemical  operations.  The  workmen  who  dyed 
cloths,  clothing,  and  tapestries  in  purple  or  other  colors,  an  in- 
dustry practiced  first  in  Egypt  and  Syria  and  then  in  all  the 
Grecian,  Roman,  and  Persian  world,  not  to  speak  of  the  ex- 
treme East,  employed  highly  developed  chemical  manipula- 
tions ;  and  the  cloths  found  on  the  mummies  and  in  the  sar- 
cophagi attest  their  perfection.  Pliny  and  Vitruvius  describe 
in  detail  the  production  of  colors,  such  as  cinnabar  or  vermilion, 
minium,  red  chalk,  indigo,  black,  green,  and  blue  colors,  vege- 
table as  well  as  mineral,  performed  by  painters.  The  chemis- 
try of  alimentation,  fruitful  in  resources  and  in  frauds,  was  next 
practiced.  The  art  was  known  of  accomplishing  at  will  those 
delicate  fermentations  which  produce  bread,  wine,  and  beer, 
and  which  modify  a  large  number  of  foods ;  also  of  falsifying 
wine  by  the  addition  of  plaster  and  other  ingredients.  The  art 
of  healing,  seeking  everywhere  for  resources  against  diseases, 
had  learned  to  transform  and  fabricate  a  large  number  of  min- 
eral and  vegetable  products,  such  as  sugar  of  poppy,  extracts 
of  nightshade,  oxide  of  copper,  verdigris,  litharge,  white  lead, 
the  sulphurets  of  arsenic  and  arsenious  acid;  remedies  and 
poisons  were  composed  at  the  same  time,  for  different  pur- 
poses, by  doctors  and  magicians.  The  manufacture  of  arms 
and  of  inflammatory  substances — petroleum,  sulphur,  resins, 
and  bitumens — had  already,  anciently  as  well  as  in  our  own 
time,  drawn  upon  the  talents  of  inventors  and  given  rise  to 
formidable  applications,  especially  in  the  arts  of  sieges  and 
marine  battles,  previous  to  the  invention  of  the  Greek  fire, 
which  was  in  its  turn  the  precursor  of  gunpowder  and  of  our 
terrible  explosive  matters. 

This  rapid  review  shows  how  far  advanced  in  the  knowledge 
of  chemical  industries  the  Roman  world  was  at  the  moment 
when  it  went  to  pieces  under  the  blows  of  the  barbarians.  But 
the  ruin  of  the  ancient  organization  came  about  by  degrees : 


CHEMISTRY  303 

while  high  scientific  study,  hardly  accessible  to  coarse  minds, 
ceased  to  be  encouraged,  and  was  gradually  abandoned ;  while 
the  Greek  philosophers,  knocked  about  between  the  religious 
persecution  of  the  Byzantine  emperors  and  the  indifferent  dis- 
dain of  the  Persian  sovereigns,  no  longer  trained  pupils ;  while 
the  great  names  of  Grecian  physics,  mathematics,  and  alchemy 
hardly  passed  the  time  of  Justinian,  it  is  still  certain  that  the 
necessity  of  professions  indispensable  to  human  life,  or  sought 
out  by  sovereigns  and  priests,  could  maintain  and  did  maintain 
effectively  most  of  the  chemical  industries. 

Proofs  of  various  kinds  can  be  brought  up  in  support  of 
these  reasonings.  Some  are  drawn  from  the  examination  of 
the  monuments,  arms,  potters'  and  glass  ware,  cloths,  gems 
and  jewels,  and  art  objects  of  every  kind  which  have  come 
down  to  us.  Such  examination  furnishes,  in  fact,  incontesta- 
ble results,  provided  the  dates  of  the  objects  are  certain,  and 
they  have  not  suffered  restoration.  Respecting  the  date,  we 
cannot  exercise  too  much  prudence  and  distrust,  whether  we 
are  examining  buildings  or  objects  in  museums.  The  accounts 
and  descriptions  by  contemporary  historians  furnish  other  data, 
but  less  precise,  for  it  is  better  to  have  the  object  in  hand  than 
the  description.  They  have  the  advantage,  however,  of  giving 
us  indications  independent  of  the  ulterior  progress  of  the  in- 
dustry. We  have  a  still  surer  and  more  exact  class  of  data 
than  the  chronicles  in  the  technical  treatises  and  works  con- 
cerning arts  and  trades  which  have  come  down  to  us,  whenever 
those  treatises  have  an  ascertained  date,  even  were  it  only  the 
date  of  their  copies.  This  source  of  facts  is  already  known  as 
to  antiquity.  It  is  not  wanting  as  to  the  Middle  Ages,  although 
it  seems  to  have  escaped  till  now  the  erudite  persons  who  have 
written  the  history  of  science,  and  it  permits  us  to  reconstitute 
that  under  a  new  form  and  with  a  new  precision.  By  the  aid 
of  those  documents  I  shall  attempt  to  show,  concerning  myself 
especially  with  chemical  industries,  what  knowledge,  practical 
or  theoretical,  subsisted  after  the  fall  of  ancient  civilization, 
and  how  the  traditions  of  the  shop  maintained  those  industries, 
almost  without  new  inventions,  but  at  least  at  a  certain  level  of 
perfection. 


304  ACHIEVEMENTS  IN  SCIENCE 

The  history  of  physical  science  in  antiquity  is  very  imper- 
fectly known  to  us.  There  existed  then  no  methodical  treatise 
for  the  purpose  of  teaching,  such  as  we  have  in  the  principal 
civilized  states.  Hence,  except  as  to  the  medical  sciences,  we 
have  only  insufficient  notions  respecting  the  processes  em- 
ployed in  the  arts  and  trades  of  the  ancients.  The  experimen- 
tal method  of  the  moderns  has  associated  those  practices  into  a 
body  of  doctrines,  and  has  shown  close  relations  between  them 
and  the  theories  for  which  they  served  as  basis  and  confirma- 
tion. This  method  was  almost  unknown  to  the  ancients,  and 
was,  at  best,  only  a  general  principle  of  scientific  learning. 
Their  industries  had  little  connection  with  theories  excepting 
in  measures  of  length,  surface,  or  volume,  which  were  deduced 
immediately  from  geometry  and  in  goldsmiths'  receipts — the 
origin  of  the  theories,  partly  real  and  partly  imaginary,  of 
alchemy. 

It  has  even  been  asked  whether  industrial  formulas  were 
not  formerly  preserved  by  purely  oral  tradition  and  carefully 
held  back  for  the  initiated.  Some  scraps  of  the  traditional  lore 
may  have  been  transcribed  into  the  notes  which  have  been 
used  in  the  composition  of  Pliny's  Natural  History  and  the 
works  of  Vitruvius  and  Isidore  de  Seville,  not  without  a  con- 
siderable mixture  of  fables  and  errors.  But  a  more  thorough 
examination  of  the  works  that  have  come  down  to  us  from  an- 
tiquity, a  more  attentive  study  of  the  manuscripts,  at  first 
neglected  because  they  did  not  relate  to  literary  or  theological 
studies  or  to  ordinary  historical  questions,  permits  the  affirma- 
tion that  they  were  not  so.  We  are  all  the  time  discovering 
new  and  considerable  documents  which  show  that  the  processes 
of  the  ancient  industrials  were  then,  as  now,  inscribed  in  work- 
men's note-books  or  manuals  intended  for  the  use  of  the  trades- 
people, and  that  they  were  transmitted  from  hand  to  hand  from 
the  most  remote  times  of  ancient  Egypt  and  Alexandrine 
Egypt,  to  those  of  the  Roman  Empire  and  the  Middle  Ages. 
The  discovery  of  these  note-books  offers  all  the  more  interest 
because  the  use  of  the  precious  metals  with  civilized  peoples 
goes  back  to  the  highest  antiquity ;  the  technic  of  the  ancient 
goldsmiths  and  jewelers  is  not  revealed  to  us  all  at  once  except 


CHEMISTRY  305 

by  the  examination  of  the  objects  that  have  come  down  to  us. 
The  earliest  precise  and  detailed  texts  describing  their  pro- 
cesses are  contained  in  an  Egpytian  papyrus  found  at  Thebes, 
and  now  in  the  museum  at  Ley  den. 

This  papyrus  is  in  the  Greek  language  and  dates  from  the 
third  century  of  the  Christian  era.  In  my  translation  of  it, 
comparing  parts  of  it  with  phrases  in  the  works  of  Pliny  and 
Vitruvius  on  the  same  subjects  and  with  Greek  alchemistic 
works  of  the  fourth  and  fifth  centuries,  I  have  reconstituted  a 
whole  science,  ancient  alchemy,  till  now  misunderstood  and 
uncomprehended,  because  it  was  founded  on  a  mixture  of  real 
facts,  profound  views  on  the  unity  of  matter,  and  chimerical  re- 
ligious fancies.  These  practices  and  theories  had  a  still  larger 
bearing  than  the  working  of  metals.  The  industries  of  the 
precious  metals  were,  in  fact,  associated  at  that  epoch  with 
those  of  the  dyeing  of  cloths,  the  coloring  of  glasses,  and  the 
imitation  of  precious  stones,  all  guided  by  the  same  tinctorial 
ideas  and  executed  by  the  same  operators. 

Thus  alchemy  and  the  chimerical  hope  of  making  gold  were 
derived  from  the  goldsmiths'  artifices  for  coloring  metals.  The 
pretended  processes  of  transmutation  which  were  current  dur- 
ing the  Middle  Ages  were  in  their  origin  only  tricks  for  prepar- 
ing alloys  of  inferior  standard — that  is,  for  imitating  and  falsify- 
ing the  precious  metals.  But,  by  an  almost  invincible  attraction 
the  operators  addicted  to  these  practices  did  not  hesitate  to 
imagine  that  one  could  pass  from  the  imitation  of  gold  to  its 
effective  formation — especially  if  he  had  the  aid  of  the  super- 
natural powers,  invoked  by  magical  formulas. 

At  any  rate,  it  was  not  known  till  now  how  these  practices 
and  theories  passed  from  Egypt,  where  they  were  flourishing 
toward  the  end  of  the  Roman  Empire,  into  the  West,  where 
we  find  them  in  full  development  from  the  thirteenth  and  four- 
teenth centuries  in  the  writings  of  the  Latin  alchemists  and  in 
the  laboratories  of  the  goldsmiths,  dyers,  and  makers  of  colored 
glass.  Their  renaissance  was  generally  attributed  to  transla- 
tions of  Arabian  works  made  at  that  epoch.  But,  without 
assuming  to  deny  the  part  played  by  the  Arabian  books  in  the 
renaissance  of  the  arts  and  sciences  in  the  West,  in  the  period 
20 


306  ACHIEVEMENTS  IN  SCIENCE 

of  the  Cnisades,  it  is  no  less  certain  that  a  continuous  tradition 
subsisted  in  the  professional  recollections  of  the  arts  and  trades 
from  the  Roman  Empire  till  the  Carlovingian  period,  and  later 
— a  tradition  of  chemical  manipulations  and  scientific  and  mys- 
tical ideas.  In  fact,  in  pursuing  my  studies  of  the  history  of 
science,  I  have  met,  in  the  examination  of  the  Latin  works  of 
the  Middle  Ages,  certain  technical  manuals  which  were  related 
most  directly  with  the  metallurgical  treatises  of  the  Greco- 
Egyptian  alchemists  and  goldsmiths.  I  purpose  to  demonstrate 
here  this  correlation,  which  nobody  has  till  now  pointed  out. 

It  is  known  that  the  recipes  of  therapeutics  and  materia 
medica  have  been  preserved  in  a  parallel  way  by  practice,  which 
has  never  ceased,  in  the  Receptaries  and  other  Latin  treatises ; 
these  treatises,  translated  from  the  Greek  during  the  period  of 
the  Roman  Empire,  and  compiled  in  the  first  and  second  cen- 
turies, passed  from  hand  to  hand,  and  were  copied  frequently 
during  the  earlier  portions  of  the  Middle  Ages.  The  transmis- 
sion of  the  military  arts  and  of  fire-producing  formulas,  particu- 
larly, was  carried  on  from  the  Greeks  and  Romans  through  the 
barbarous  ages.  In  short,  the  necessity  of  the  applications  has 
always  caused  the  subsistence  of  a  certain  experimental  tradi- 
tion of  the  arts  of  ancient  civilization. 

The  oldest  known  technical  treatises  in  Latin  of  the  Middle 
Ages  on  subjects  in  chemistry  are  the  " Formulas  for  Dyeing" 
(Compositiones  ad  tingendo),  of  which  we  have  a  manuscript 
written  toward  the  end  of  the  eighth  century,  and  the  "  Key  to 
Painting  "  (Mappce  clavicula),  the  oldest  manuscript  of  which  is 
of  the  tenth  century.  The  "  Formulas  for  Dyeing "  is  not  a 
methodical  work,  but  a  book  of  receipts  and  documents  collected 
by  a  dyer  for  use  in  his  art  and  intended  to  furnish  him  with 
working  processes  and  information  concerning  the  origin  of  his 
prime  materials.  It  concerns  such  subjects  as  the  coloring  or 
dyeing  of  artificial  stones  for  mosaic  work ;  gliding  and  silver- 
ing and  polishing  them;  making  of  colored  glass  in  green, 
milky  white,  various  shades  of  red,  purple,  yellow — the  colors 
being  both  deep  and  superficial,  and  often  brought  out  by  the 
aid  of  simple  varnishes ;  coloring  of  skins  in  purple,  green,  yel- 
low, and  various  reds;  dyeing  of  woods,  bones,  and  horns; 


CHEMISTRY  307 

notices  of  minerals,  metals,  and  earths  used  in  goldsmiths' 
work  and  painting.  Curious  ideas  are  set  forth  on  the  function 
of  the  sun  and  of  heat,  peculiar  to  certain  warm  earths  in  the 
production  of  minerals  endowed  with  corresponding  virtues; 
while  a  cold  earth  produces  minerals  of  weak  quality.  This  re- 
minds us  of  the  theories  of  Aristotle  on  dry  exhalation  as 
opposed  to  moist  exhalation  in  the  generation  of  minerals — 
theories  that  made  an  important  figure  in  the  Middle  Ages. 
The  author  distinguishes  a  feminine  and  light  lead  mineral  as 
against  a  masculine  and  heavy  mineral ;  a  distinction  like  that 
mentioned  by  Pliny  between  male  and  female  antimony,  the 
male  and  female  blue  of  Theophrastus,  and  many  others. 
Minerals  were  continually  likened  in  the  chemistry  of  the  Mid- 
dle Ages  to  living  beings. 

In  this  work  we  read,  likewise,  of  articles  developed  in  cer- 
tain operations,  such  as  the  extraction  of  mercury,  lead,  the 
roasting  of  sulphur,  preparations  of  white  lead  and  vinegar,  of 
verdigris  with  vinegar  and  copper — already  described  by  Theo- 
phrastus and  Dioscorides — of  cadmies,  impure  oxides  of  lead 
and  zinc,  of  burned  copper  (ces  ustum),  of  litharge,  of  orpi- 
ment,  of  artificial  cinnabar,  etc.  The  writer  mentions  a  few 
alloys,  such  as  bronze,  white  copper,  and  gold-colored  copper — 
a  subject  often  treated  of  by  the  Greek  alchemists,  who  passed 
from  it  to  the  idea  of  transmutation.  The  name  of  bronze  (brun- 
disium)  appears  for  the  first  time.  While  its  origin  has  been 
the  subject  of  controversy  among  philologists,  the  accompany- 
ing facts  given  in  the  text  show  that  bronze  was  in  the  begin- 
ning an  alloy  made  at  Brundisium  for  the  manufacture  of  the 
mirrors  of  which  Pliny  speaks.  The  preparation  of  parchment 
and  of  varnish,  the  fabrication  of  vegetable  colors  for  the  use 
of  painters  and  illuminators,  and  their  employment  on  walls, 
wood,  canvas,  etc.,  in  encaustic  or  with  isinglass,  are  the  sub- 
jects of  separate  articles. 

A  group  of  formulas  for  gilding  follow :  gilding  of  glass, 
wood,  skins,  clothing,  lead,  tin,  and  iron;  and  the  preparation 
of  golden  wires,  processes  for  writing  in  golden  letters  (chrys- 
ography)  on  parchment,  paper,  glass,  or  marble.  Then  come 
silver  foil,  tin  foil,  and  processes  for  reducing  gold  and  silver  to 


308  ACHIEVEMENTS  IN  SCIENCE 

powder,  in  which  mercury  and  verdigris  were  employed — the 
powder  obtained  by  amalgamation  being  used  in  processes  for 
silvering  and  gilding.  The  process  has  played  its  part  in  politi- 
cal economy ;  for  it  has  been  used  to  assist  the  passage  of  gold 
and  silver  from  one  country  to  another,  in  spite  of  the  prohibi- 
tion of  the  exportation  of  the  precious  metals. 

The  author  goes  on  to  say :  "  We  have  described  every- 
thing relative  to  tinctures  and  decorations ;  we  have  spoken  of 
the  substances  which  are  employed  in  them — stones,  minerals, 
salts,  and  herbs ;  we  have  shown  where  they  are  found ;  whence 
are  got  resins,  oleoresins,  and  earths ;  what  are  sulphur,  black 
water,  salt  waters,  glue,  and  all  the  products  of  wild  and  culti- 
vated plants,  domestic  and  marine ;  beeswax,  axunge,  all  fresh 
and  acid  waters;  among  woods,  the  pine,  fir,  juniper,  and  cy- 
press, .  .  .  acorns  and  figs.  Extracts  are  made  of  all  these 
things  with  a  water  made  of  fermented  urine  and  vinegar,  mixed 
with  rain-water." 

These  enumerations  and  descriptions  mark  the  nature  of 
the  knowledge  sought  by  the  writer,  and  preserve  the  trace  of 
ancient  treatises  on  drugs  and  medicines,  similar  to  those  of 
Dioscorides,  but  more  especially  devoted  to  industry.  Unfortu- 
nately, we  have  here  hardly  anything  else  than  titles  and  sum- 
mary indications,  such  as  would  figure  in  a  dyer's  scrap-book, 
placing,  one  after  another,  indications  drawn  from  different 
authors.  Many  of  the  specific  names  found  in  the  treatise  are 
wanting  in  the  most  complete  dictionaries.  The  terms  salt, 
fresh,  and  acid  waters,  water  formed  of  fermented  urine  and 
vinegar,  deserve  special  notice  because  they  point  to  the  begin- 
ning of  chemistry  by  moist  processes.  They  figured  in  Pliny 
and  the  ancient  authors,  to  the  same  purposes.  The  liquids 
are  always  natural  ones  or  the  results  of  the  mixture  of  such, 
before  or  after  spontaneous  combustion.  There  is  no  mention 
of  the  active  liquids  obtained  by  distillation,  which  were  called 
divine  or  sulphurous  waters,  and  held  an  important  place  with 
the  Greco-Egyptian  chemists,  and  became  the  origin  of  our 
acids,  alkalies,  and  other  agents ;  they  had  not  yet  entered  into 
industrial  use,  and  are  seldom  met  with  previous  to  the  four- 
teenth century. 


CHEMISTRY  309 

The  group  of  recipes  transmitted  by  the  formulas  for  dye- 
ing, passed  into  a  more  extended  collection  called  the  "  Key  to 
Painting,"  of  which  exist  a  manuscript  of  the  tenth  century  in 
the  library  of  Schlestadt  and  one  of  the  twelfth  century,  of 
which  an  edition  was  published  in  1847  by  Mr.  Way.  The 
former  manuscript  is  free  from  all  Arabian  influence,  which  has 
caused  the  interpolation  of  five  additional  articles  in  the  second 
one.  The  work  contains  a  treatise  on  the  precious  metals  com- 
prising now  a  hundred  articles — about  half  of  the  original  work, 
the  other  half  having  been  lost — and  a  treatise  on  recipes  for 
dyeing,  representing  principally  those  in  the  Formulas;  to- 
gether with  sixteen  articles  on  military  ballistics  and  fireworks, 
forming  a  special  group ;  articles  on  the  hydrostatic  balance 
and  the  densities  of  the  metals ;  and  industrial  and  magic  reci- 
pes, added  at  the  end  of  the  book. 

The  treatise  on  the  precious  metals  is  of  great  interest  be- 
cause of  the  striking  analogies  it  presents  with  the  Leyden 
Egyptian  papyrus  found  at  Thebes,  and  with  other  ancient 
works.  Many  of  the  recipes  are  literally  translated  from  these 
ancient  works ;  an  identity  proving  indisputably  the  continuous 
preservation  of  alchemic  practices,  including  transmutation, 
from  Egypt  down  to  the  artisans  of  the  Latin  West.  The 
theories  proper,  on  the  other  hand,  did  not  reappear  in  the 
West  till  toward  the  end  of  the  twelfth  century,  after  they  had 
passed  through  the  Syrians  and  the  Arabs.  But  the  knowl- 
edge of  the  processes  themselves  was  never  lost.  This  fact  is 
demonstrated  by  the  study  of  the  alloys  intended  to  imitate  and 
falsify  gold;  for  coloring  (copper)  gold-color;  for  fabricating 
gold ;  for  making  test  gold ;  for  rendering  gold  heavier ;  and 
for  doubling  gold.  The  recipes  are  filled  with  Greek  words 
that  betray  their  origin. 

The  object  for  the  most  part  is  simply  to  make  base  gold, 
as,  for  instance,  by  preparing  an  alloy  of  gold  and  silver,  colored 
with  copper.  The  goldsmith,  however,  tried  to  make  this  pass 
for  pure  gold.  Then  manufactures  of  complex  alloys  which 
were  made  to  pass  for  pure  gold  were  made  easier  by  the  inter- 
vention of  mercury  and  sulphurets  of  arsenic,  the  use  of  which 
goes  back  to  the  earliest  times  of  the  Roman  Empire.  Thus 


310  ACHIEVEMENTS  IN  SCIENCE 

Pliny  relates  in  a  few  lines  an  experiment  performed  by  order 
of  Caligula  for  fabricating  gold  with  sulphuret  of  arsenic  (or 
orpiment).  There  was  thus  a  whole  special  chemistry,  now 
abandoned,  which  was  conspicuous  in  the  practices  and  preten- 
sions of  the  alchemists.  A  patent  has  been  obtained  in  our 
own  times  for  an  alloy  of  copper  and  antimony,  containing  six 
hundredths  of  the  latter  metal,  which  presents  most  of  the 
apparent  properties  of  gold  and  is  worked  in  the  same  manner. 
Alchemic  gold  belonged  to  a  family  of  similar  alloys.  Those 
who  made  it  fancied  besides  that  some  agents  played  the  part 
of  ferments  to  multiply  gold  and  silver.  Before  deceiving  other 
people  they  deluded  themselves.  Sometimes  the  artisan  was 
satisfied  to  use  a  cement  or  superficial  action,  painting  the  sur- 
face of  silver  in  gold  or  the  surface  of  copper  in  silver,  without 
modifying  the  metals  in  their  thickness.  This  is  what  gold- 
smiths still  call  giving  color.  They  would  even  do  no  more 
than  apply  to  the  surface  of  the  metal  a  gold-colored  varnish, 
prepared  with  the  bile  of  animals  or  with  certain  resins,  as  is 
still  done.  From  these  colorings  the  operator,  led  by  a  mystic 
analogy,  passed  to  the  idea  of  transmutation,  in  the  false 
Democritus  and  in  the  Key  to  Painting.  The  author  of  the 
last  work  concluded,  for  example,  with  the  words,  "  You  will 
thus  obtain  excellent  gold  and  fit  for  the  test."  The  author 
added,  further,  "Hide  this  sacred  secret,  which  should  be  de- 
livered to  no  one,  nor  to  any  prophet."  The  word  prophet  be- 
trays the  Egyptian  origin  of  the  recipe.  It  refers  to  the  Egyp- 
tian priests,  who,  according  to  a  passage  in  Clement  of  Alexan- 
dria on  the  Hermetic  books  that  were  borne  with  great  pomp 
in  the  processions,  were  called  prophets. 

In  further  proof  of  the  Greco-Egyptian  origin  of  goldsmiths' 
recipes  contained  in  the  "  Key  to  Painting,"  is  the  existence  in 
the  Latin  collection  of  ten  recipes — some  of  the  elaborate  ones 
— which  are  phrased  in  precisely  the  same  terms  in  the  Greek 
papyrus  in  Leyden ;  the  former  text  being  translated  from  the 
latter,  even  to  the  detail  of  certain  technical  expressions,  which 
are  still  perpetuated  in  the  goldsmiths'  manuals  of  the  present. 
This  does  not  mean  that  the  text  transcribed  in  the  "  Key  to 
Painting  "  was  originally  translated  from  the  very  papyrus  that 


CHEMISTRY  311 

we  possess,  which  was  not  found  till  the  nineteenth  century  at 
Thebes,  Egypt;  but  the  coincidence  of  the  text  proves  that 
there  existed  books  of  secret  goldsmiths'  recipes  transmitted 
from  hand  to  hand  of  the  tradesmen,  which  continued  through 
the  Middle  Ages,  and  of  which  the  Key  is  an  example.  It  was 
firmly  believed  in  the  time  of  Diocletian  that  the  Egyptians 
had  the  secret  of  enriching  themselves  by  making  gold  and  sil- 
ver ;  and  in  consequence  of  this  belief,  after  a  revolt,  the  Em- 
peror ordered  all  their  books  burned.  Nevertheless,  as  we 
have  seen,  the  formulas  did  not  disappear. 

The  title  of  one  of  the  recipes  in  the  old  table,  "  How  to 
make  unbreakable  glass,"  deserves  to  be  dwelt  upon,  on  account 
of  the  legends  and  traditions  that  are  associated  with  it,  and 
which  have  been  perpetuated  down  to  our  own  time.  Unbreak- 
able glass  appears  to  have  been  really  discovered  under  Tibe- 
rius, and  gave  rise  to  a  legend  according  to  which  its  properties 
were  amplified  and  it  was  made  malleable.  Tiberius,  according 
to  Pliny,  caused  the  factory  to  be  destroyed,  for  fear  that  the 
invention  would  diminish  the  value  of  gold  and  silver.  "  If  it 
was  known,"  wrote  Petronius,  "gold  would  become  as  cheap 
as  mud."  According  to  Dion  Cassius,  Tiberius  slew  the  author. 
Petronius,  who  is  repeated  by  other  authors,  says  that  he  was 
decapitated,  and  adds  that  "  if  vessels  of  glass  were  not  fragile 
they  would  be  preferable  to  vessels  of  gold  and  silver." 

These  stories  relate  evidently  to  the  same  historical  fact, 
reported  by  contemporaries,  but  disfigured  by  legend ;  the  in- 
vention was  probably  suppressed  for  fear  of  its  economical  con- 
sequences. It  is  very  curious  to  find  it  mentioned  in  the  gold- 
smiths' recipes  of  the  Middle  Ages,  as  if  the  secret  tradition  had 
been  preserved  in  the  shops.  Some  of  them  claimed  that  glass 
could  be  made  malleable  and  ductile  and  changed  into  a  metal. 
A  process  for  making  glass  that  will  not  break  has  been  dis- 
covered in  our  own  times,  and  is  announced  unequivocally  and 
in  definite  shape.  In  truth,  malleable  glass  was  not  really  in 
question ;  but  even  that  is  not  a  chimera.  Industrial  processes 
for  beating  and  molding  glass,  based  on  the  plasticity  and  mal- 
leability which  it  possesses  at  a  temperature  near  fusion,  have 
been  described  in  late  years.  An  article  in  the  "  Key  to  Paint- 


312  ACHIEVEMENTS  IN  SCIENCE 

ing  "  seems  to  point  to  a  similar  process.  Real  properties,  per- 
ceived doubtless  from  antiquity  and  preserved  as  shop  secrets, 
gave  rise  to  the  legend. 

The  collection  bearing  the  name  of  Eraclius  or  Heraclius  is 
in  two  parts,  of  different  composition  and  date.  The  first  part 
consists  of  two  books  in  verse,  having  the  character  of  the 
writing  of  the  end  of  the  Carlovingian  epoch,  or  of  the  ninth 
and  tenth  centuries.  It  treats  of  vegetable  colors,  of  gold  leaf, 
of  writing  in  letters  of  gold,  of  gilding,  of  painting  on  glass, 
and  of  the  preparation  of  precious  stones.  All  the  recipes  are 
of  ancient  origin,  a  little  vague,  and  without  novelty.  A  book 
in  prose  is  more  compact  and  precise.  It  was  added  later  by  a 
continuator,  toward  the  twelfth  century,  for  there  is  a  discus- 
sion in  it  of  the  coloring  of  Cordovan  leather,  and  cinnabar, 
which  is  red,  is  called  in  it  azure — a  translation  of  an  Arabic 
word,  frequent  in  the  twelfth  century,  which  has  given  rise  to 
all  sorts  of  misconceptions  and  confusion  with  our  modern 
azure  blue.  It  has  the  stories  about  malleable  glass ;  and  most 
of  the  subjects  were  already  treated  in  the  "  Key  to  Painting." 

The  "  Picture  of  Different  Arts  "  of  the  monk  Theophilus 
seems  to  be  the  work  of  an  author  who  lived  at  the  end  of  the 
eleventh  century  and  beginning  of  the  twelfth.  It  is  more 
exact  and  detailed  than  the  work  of  Eraclius,  and  is  composed 
of  two  parts — the  first  devoted  to  painting,  and  the  second  con- 
cerning the  making  of  objects  required  in  worship  and  the  con- 
struction of  buildings  devoted  to  it.  It  describes  in  detail  the 
furnace  for  melting  glass  and  the  manufacture  of  glass,  the 
making  of  painted  glass  and  colored  earthen  vessels,  the  work- 
ing of  iron,  the  melting  of  gold  and  silver  and  the  working  of 
them,  enamel,  the  fabrication  of  vessels  used  in  worship — the 
chalice,  monstrance,  etc. — organs,  bells,  cymbals,  etc.  The 
facts  are  curious,  for  they  show  that  the  industry  of  glass  and 
metals  had  finally  concentrated  around  the  religious  edifices. 
But  the  chemical  technique  is  the  same  as  that  of  the  other 
books,  though  savoring  of  more  modern  influences ;  it  brings 
us  directly  to  the  thirteenth  and  fourteenth  centuries,  from 
which  period  monuments  and  writings  multiply  more  rapidly 
down  into  modern  times.  The  derivation  of  technical  tradi- 


CHEMISTRY  313 

tions  from  antiquity  becomes  less  and  less  manifest  as  interme. 
diaries  multiply  and  the  arts  tend  to  assume  an  original 
character. 

The  facts  I  have  presented  deserve  our  attention  as  a  whole, 
in  view  of  the  course"  and  renaissance  of  scientific  traditions 
Sciences  begin  in  fact  with  practice.  The  first  object  is  to 
satisfy  the  necessities  of  life  and  the  artistic  wants  that  awaken 
early  in  civilizable  races.  But  this  same  practice  at  once  calls 
out  more  general  ideas,  which  appeared  first  among  mankind 
in  a  mystic  form.  With  the  Egyptians  and  Babylonians  the 
same  persons  were  at  once  the  priests  and  the  men  of  science. 
Thus  the  chemical  industries  were  first  exercised  around  the 
temples.  The  "  Book  of  the  Sanctuary,"  the  "  Book  of  Hermes," 
and  the  "  Book  of  Kemi,"  all  synonymous  denominations  with 
the  Greco-Egyptian  alchemists,  represent  the  earliest  manuals 
of  those  industries.  It  was  the  Greeks,  as  in  all  other  scientific 
branches,  who  gave  these  treatises  a  revision  freed  from  the  old 
hieratic  forms,  and  who  tried  to  draw  from  them  a  rational 
theory,  capable  in  its  turn,  by  a  similar  application,  of  pushing 
the  practice  forward  and  of  serving  as  a  guide  to  it.  But  the 
chemical  science  of  the  Greco-Egyptians  never  rid  itself  of 
the  errors  relative  to  transmission — which  were  sustained  by 
the  theory  of  primal  matter — or  of  the  religious  and  magic 
formulas  formerly  associated  in  the  East  with  every  industrial 
operation.  Yet  when  scientific  study  proper  perished  with 
Roman  civilization  in  the  West,  the  wants  of  life  kept  up  the 
imperishable  practice  of  the  shops  with  the  progress  required 
in  the  time  of  the  Greeks,  and  the  chemical  arts  subsisted ; 
while  the  theories,  too  subtile  or  too  strong  for  the  minds  of 
the  time,  tended  to  disappear,  or  rather  to  return  toward  the 
ancient  superstitions.  In  the  "  Key  to  Painting,"  as  in  the  Egyp- 
tian papyrus  and  the  texts  of  Zosimus,  are  mentions  of  prayers 
to  be  recited  during  the  operations ;  and  in  this  way  alchemy 
remained  intimately  connected  with  magic  in  the  Middle  Ages 
as  well  as  in  antiquity. 

During  the  Latin  Middle  Ages,  toward  the  thirteenth  cen- 
tury, when  civilization  began  to  revive,  in  the  midst  of  a  new 
organization,  our  races  took  up  anew  the  taste  for  general  ideas, 


314  ACHIEVEMENTS  IN  SCIENCE 

and  these,  in  the  sphere  of  chemistry,  were  sustained  by  prac- 
tices, or  rather  they  obtained  their  support  in  the  permanent 
problems  raised  by  them.  Thus  the  alchemistic  theories  were 
suddenly  revived,  with  new  vigor  and  development,  and  their 
progressive  evolution,  .while  improving  industry,  gradually 
eliminated  the  superstitions  of  former  times.  Thus  was  finally 
constituted  our  modern  chemistry,  a  rational  science,  estab- 
lished on  purely  experimental  bases.  The  science  was  there- 
fore born  in  its  beginning  of  industrial  practices ;  it  kept  course 
with  their  development  during  the  reign  of  ancient  civilization ; 
when  science  went  down  with  civilization  practice  survived  and 
furnished  science  a  solid  ground  on  which  it  was  able  to  achieve 
a  new  development  when  the  times  and  the  minds  had  become 
favorable.  The  historical  connection  of  science  and  practice  in 
the  history  of  civilizations  is  therefore  manifest.  There  is  in 
it  a  general  law  of  the  development  of  the  human  mind. 


CHEMISTRY 
Chemical    History  of  a   Candle 

(Selection) 
By  MICHAEL  FARADAY 

WHAT  is  all  this  process  going  on  within  us  which  we 
cannot  do  without,  either  day  or  night,  which  is  so  pro- 
vided for  by  the  Author  of  all  things,  that  He  has  arranged 
that  it  shall  be  independent  of  all  will  ?  If  we  restrain  our  res- 
piration, as  we  can  to  a  certain  extent,  we  should  destroy  our- 
selves. When  we  are  asleep,  the  organs  of  respiration,  and  the 
parts  that  are  associated  with  them,  still  go  on  with  their  action, 
so  necessary  is  this  process  of  respiration  to  us,  this  contact  of 
air  with  the  lungs.  I  must  tell  you,  in  the  briefest  possible  man- 
ner, what  this  process  is.  We  consume  food :  the  food  goes 
through  that  strange  set  of  vessels  and  organs  within  us,  and 
is  brought  into  various  parts  of  the  system,  into  the  digestive 
parts  especially ;  and  alternately  the  portion  which  is  so  changed 
is  carried  through  our  lungs  by  one  set  of  vessels,  while  the 
air  that  we  inhale  and  exhale  is  drawn  into  and  thrown  out 
of  the  lungs  by  another  set  of  vessels,  so  that  the  air  and  the 
food  come  close  together,  separated  only  by  an  exceedingly  thin 
surface :  the  air  can  thus  act  upon  the  blood  by  this  process,  pro- 
ducing precisely  the  same  results  in  kind  as  we  have  seen  in 
the  case  of  the  candle.  The  candle  combines  with  parts  of  the 
air,  forming  carbonic  acid,  and  evolves  heat ;  so  in  the  lungs 
there  is  this  curious,  wonderful  change  taking  place.  The  air 
entering,  combines  with  the  carbon  (not  carbon  in  a  free  state, 
but,  as  in  this  case,  placed  ready  for  action  at  the  moment), 
and  makes  carbonic  acid,  and  is  so  thrown  out  into  the  atrnos- 

315 


316  ACHIEVEMENTS  IN  SCIENCE 

phere,  and  thus  this  singular  result  takes  place :  we  may  thus 
look  upon  the  food  as  fuel.  Let  me  take  that  piece  of  sugar, 
which  will  serve  my  purpose.  It  is  a  compound  of  carbon,  hy- 
drogen, and  oxygen,  similar  to  a  candle,  as  containing  the  same 
elements,  though  not  in  the  same  proportion ;  the  proportions 
in  sugar  being  as  shown  in  this  table : 


Carbon 72 

Hydrogen , 1 1 

Oxygen 88 


This  is,  indeed,  a  very  curious  thing,  which  you  can  well  re- 
member, for  the  oxygen  and  hydrogen  are  in  exactly  the  pro- 
portions which  form  water,  so  that  sugar  may  be  said  to  be 
compounded  of  seventy-two  parts  of  carbon  and  ninety-nine 
parts  of  water ;  and  it  is  the  carbon  in  the  sugar  that  combines 
with  the  oxygen  carried  in  by  the  air  in  the  process  of  respi- 
ration, so  making  us  like  candles;  producing  these  actions, 
warmth,  and  far  more  wonderful  results  besides,  for  the  suste- 
nance of  the  system,  by  a  most  beautiful  and  simple  process. 
To  make  this  still  more  striking,  I  will  take  a  little  sugar ;  or 
to  hasten  the  experiment  I  will  use  some  syrup,  which  contains 
about  three-fourths  sugar  and  a  little  water.  If  I  put  a  little 
oil  of  vitriol  on  it,  it  takes  away  the  water,  and  leaves  the  car- 
bon in  a  black  mass,  and  before  long  we  shall  have  a  solid 
mass  of  charcoal,  all  of  which  has  come  out  of  sugar.  Sugar, 
as  you  know,  is  food,  and  here  we  have  absolutely  a  solid 
lump  of  carbon  where  you  would  not  have  expected  it.  And 
if  I  make  arrangements  so  as  to  oxidize  the  carbon  of  sugar, 
we  shall  have  a  much  more  striking  result.  Here  is  sugar, 
and  I  have  here  an  oxidizer — a  quicker  one  than  the  atmos- 
phere :  and  so  we  shall  oxidize  this  fuel  by  a  process  differ- 
ent from  respiration  in  its  form, — though  not  different  in  its 
kind.  It  is  the  combustion  of  the  carbon  by  the  contact  of 
oxygen  which  the  body  has  supplied  to  it.  If  I  set  this  into 
action  at  once,  you  will  see  combustion  produced.  Just  what 
occurs  in  my  lungs — taking  in  oxygen  from  another  source, 
namely,  the  atmosphere— takes  place  here  by  a  more  rapid 
process. 


CHEMISTRY  317 

You  will  be  astonished  when  I  tell  you  what  this  curious 
play  of  carbon  amounts  to.  A  candle  will  burn  some  four,  five, 
six,  or  seven  hours.  What  a  wonderful  change  of  carbon  must 
take  place  under  these  circumstances  of  combustion  or  respira- 
tion !  A  man  in  twenty-four  hours  converts  as  much  as  seven 
ounces  of  carbon  into  carbonic  acid ;  a  milch  cow  will  convert 
seventy  ounces,  and  a  horse  seventy-nine  ounces,  solely  by  the 
act  of  respiration.  That  is,  the  horse  in  twenty-four  hours 
burns  seventy-nine  ounces  of  charcoal,  or  carbon,  in  his  organs 
of  respiration,  to  supply  his  natural  warmth  in  that  time.  All 
the  warm-blooded  animals  get  their  warmth  in  this  way,  by  the 
conversion  of  carbon,  not  in  a  free  state,  but  in  a  state  of  com- 
bination. And  what  an  extraordinary  notion  this  gives  us  of 
the  alterations  going  on  in  our  atmosphere.  As  much  as 
5,000,000  pounds,  or  five  hundred  and  forty-eight  tons,  of  car- 
bonic acid  is  formed  by  respiration  in  London  alone  in  twenty- 
four  hours.  And  where  does  all  this  go  ?  Up  in  the  air.  If 
the  carbon  had  been  like  the  lead  which  I  showed  you,  or  the 
iron,  which  in  burning  produces  a  solid  substance,  what  would 
happen?  Combustion  could  not  goon.  As  charcoal  burns  it 
becomes  a  vapor,  and  passes  off  into  the  atmosphere,  which  is 
the  great  vehicle,  the  great  carrier  for  conveying  it  away  to 
other  places.  Then  what  becomes  of  it  ?  Wonderful  is  it  to 
find  that  the  change  produced  by  respiration,  which  seems  so 
injurious  to  us  (for  we  cannot  breathe  air  twice  over),  is  the 
very  life  and  support  of  plants  and  vegetables  that  grow  upon 
the  surface  of  the  earth.  It  is  the  same  also  under  the  surface, 
in  the  great  bodies  of  water;  for  fishes  and  other  animals 
respire  upon  the  same  principle,  though  not  exactly  by  contact 
with  the  open  air. 


CHEMISTRY 
Liquid  Air 

By  IRA  REMSEN  * 

WATER,  the  substance  most  familiar  to  us,  is  known  in 
the  liquid,  in  the  solid,  and  in  the  gaseous  state. 
Everybody  knows  that  by  heating  the  solid  it  passes  into  the 
liquid  state,  and  that  by  heating  the  liquid  it  passes  into  the 
form  of  gas  or  vapor.  So  also  everybody  knows  that  when  the 
vapor  of  water  is  cooled  it  is  liquefied,  and  that  by  cooling  liquid 
water  sufficiently  it  becomes  solid  or  turns  to  ice.  In  the  same 
way  many  of  the  substances  that  are  known  to  us  as  liquids, 
such  as  alcohol  and  ether,  can  be  converted  into  the  form  of 
gas  or  vapor  by  heat.  In  fact,  this  is  true  of  most  liquids. 
The  temperature  at  which  a  solid  passes  into  the  liquid  state 
is  called  its  melting  point,  and  the  temperature  at  which  a  liquid 
passes  into  the  gaseous  state  is  called  its  boiling  point.  The 
boiling  point  of  water,  for  example,  is  100°  C.  (212°  F.)  in  the 
open  air.  But  the  boiling  point  varies  with  the  pressure  exerted 
upon  the  surface.  The  pressure  that  we  ordinarily  have  to  deal 
with  is  that  of  the  atmosphere.  If  the  pressure  is  increased 
the  boiling  point  is  raised,  and  if  the  pressure  is  decreased  the 
boiling  point  is  lowered.  In  dealing,  then,  with  the  conversion 
of  a  gas  into  a  liquid,  or  that  of  a  liquid  into  a  gas,  both  the 
temperature  and  the  pressure  have  to  be  considered. 

Just  as  water  is  most  familiar  to  us  in  the  liquid  form,  so 
there  are  substances  that  are  most  familiar  to  us  in  the  gaseous 
form.  In  fact,  the  only  gaseous  substances  that  can  be  said  to 


*  President  of  Johns  Hopkins  University. 

318 


CHEMISTRY  319 

be  familiar  to  everybody  are  the  gases  contained  in  the  air. 
The  principal  constituents  of  the  air  are  nitrogen  and  oxygen, 
which  form  respectively  about  four-fifths  and  one-fifth  of  its 
bulk.     Besides  these  gases,  however,  the  air  contains  water 
vapor,  carbonic-acid  gas,  ammonia,  argon  in  small  quantities, 
and  many  other  substances  in  still  smaller  quantities.     For  the 
mrposes  of  this  article  it  is  only  necessary  to  have  in  mind  the 
itrogen,  oxygen,  water  vapor,  and  carbonic  acid.     Of  these, 
e  water  vapor  is  easily  converted  into  liquid,  as,  for  example, 
the  formation  of  rain,  while  the  other  constituents  are  lique- 
ied  with  difficulty.     The  name  "  liquid  air  "  is  applied  to  the 
ibstance  that  is  obtained  by  converting  the  air  as  a  whole  into 
liquid ;  but  in  this  process  the  water  and  the  carbonic  acid 
:ome  solid  and  can  be  filtered  from  the  liquid  so  that  the 
itter  consists  almost  wholly  of  oxygen  and  nitrogen.    A  few 
/•ears  ago  this  liquid  was  obtainable  in  only  very  small  quanti- 
ties.   To-day,  thanks  especially  to  the  efforts  of  Mr.  Charles 
\.  Tripler,  of  New  York,  it  can  be  produced  in  any  desired 
quantity,  and  at  moderate  cost.     In  consequence  of  this,  it  has 
>me  to  be  talked  about  in  a  familiar  way,  and  many  persons 
lave  had  the  privilege  of  seeing  and  feeling  it,  and  of  learning 
)mething  about  its  wonderful  properties.     The  object  of  this 
irticle  is  to  explain  the  method  employed  in  the  production  of 
liquid  air,  to  give  an  account  of  some  of  its  properties,  and  to 
idicate  some  of  the  uses  to  which  it  may  possibly  be  put. 
In  the  older  text-books  of  physics  and  of  chemistry  certain 
were  classed  as  "permanent,"  under  the  impression  that 
lese  could  not  be  liquefied,  and  this  impression  was  based 
>on  the  fact  that  all  efforts  to  liquefy  them  had  failed.    A 
>rief  account  of  these  efforts  will  be  helpful. 

Among  the  so-called  permanent  gases  was  chlorine.  An 
English  chemist,  Northmore,  first  succeeded,  early  in  this  cen- 
in  liquefying  chlorine.  His  work  was,  however,  lost  sight 
)f,  and  in  1823  Faraday  at  the  Royal  Institution  showed  inde- 
pendently that  this  transformation  of  gaseous  chlorine  into  the 
liquid  can  be  effected  comparatively  easily.  The  method  used 
by  him  is  this :  When  chlorine  gas  is  passed  into  cold  water  it 
forms  with  the  water  a  solid  product  known  as  chlorine  hydrate. 


320  ACHIEVEMENTS  IN  SCIENCE 

If  kept  well  cooled  this  hydrate  can  be  dried.  If  then  its  tem- 
perature is  raised  even  to  the  ordinary  temperature  of  the  room, 
the  solid  hydrate  is  decomposed  into  liquid  water  and  gaseous 
chlorine.  Faraday  put  some  of  the  solid  hydrate  into  a  stout 
glass  tube  sealed  at  one  end  and  bent  at  the  middle.  The 
other  end  of  the  tube  was  then  closed.  The  tube  was  then 
suspended  so  that  the  two  ends  were  turned  downward.  On 
gently  warming  the  end  in  which  was  the  solid  hydrate  this 
was  decomposed  into  chlorine  and  water.  But  the  gas  given 
off  would  under  ordinary  conditions  have  occupied  a  much 
larger  space  than  the  solid  hydrate.  Being  prevented  from  ex- 
panding by  the  tube  in  which  it  was  inclosed,  it  was  under  very 
considerable  pressure.  The  end  of  the  tube  that  was  not 
warmed  was  cooled,  and  in  this  end,  in  consequence  of  the  press- 
ure and  the  comparatively  low  temperature,  chlorine,  which  is 
gaseous  under  the  ordinary  pressure  of  the  air,  appeared  as  a 
liquid.  The  general  method  made  use  of  by  Faraday  in  this 
classical  experiment  is  that  which  is  always  made  use  of  for  the 
purpose  of  liquefying  gases,  but  for  some  gases  pressure  is  very 
much  higher  and  temperatures  very  much  lower  are  required. 
Faraday  himself  succeeded  in  liquefying  all  the  gases  then 
known  except  oxygen,  hydrogen,  nitrogen,  nitric  oxide,  and 
marsh  gas.  He  subjected  oxygen  to  a  pressure  of  about  one 
thousand  pounds  to  the  square  inch,  or  nearly  seventy  atmos- 
pheres, but  it  showed  no  signs  of  liquefaction.  Later  experi- 
menters increased  the  pressure  to  4,000  pounds  to  the  square 
inch,  with  no  better  results,  so  that  it  is  not  surprising  that  it 
came  to  be  held  that  some  gases  are  permanent. 

Within  comparatively  recent  years  several  gases  have  been 
liquefied  on  the  large  scale  by  means  of  pressure.  These  are 
ammonia,  carbonic  acid,  nitrous  oxide,  and  chlorine.  Ammonia 
is  used  for  producing  low  temperatures,  as  in  breweries  and  in 
cold-storage  plants  and  in  the  manufacture  of  ice;  carbonic 
acid,  for  fire  extinguishers  and  for  charging  beer  with  the  gas ; 
nitrous  oxide,  for  producing  anaesthesia ;  and  chlorine  in  con- 
nection with  several  branches  of  chemical  manufacture.  The 
production  of  low  temperatures  by  means  of  liquid  ammonia 
and  of  liquid  carbonic  acid  will  be  more  fully  dealt  with  further 


CHEMISTRY  321 

on,  when  the  principles  involved  will  be  briefly  presented.  It 
is  to  be  borne  in  mind  that  these  substances  are  liquefied  by 
means  of  pressure  alone,  at  temperatures  that  are  easily 
reached,  so  that  it  appears  that  by  mechanical  pressure  it  is 
possible  to  produce  low  temperatures.  In  1869  an  important 
fact  was  discovered  by  Andrews.  It  was  that  for  every  gas 
there  is  a  temperature  above  which  it  is  impossible  to  liquefy 
it  by  pressure.  Thus,  if  chlorine  is  at  any  temperature  above 
146°  C.  (294°  F.)  it  cannot  be  liquefied.  This  temperature  is 
called  the  "critical  temperature"  of  chlorine.  The  pressure 
to  which  the  gas  must  be  subjected  at  the  "critical  tempera- 
ture "  in  order  that  the  gas  may  be  liquefied  is  called  the  "  criti- 
cal pressure."  In  the  case  of  chlorine  this  is  93.5  atmospheres. 
Now  the  critical  temperature  of  the  gases  that  were  called  per- 
manent gases  are  very  low — lower  than  could  be  reached  by  the 
means  at  the  command  of  earlier  experimenters.  The  critical 
temperature  of  oxygen,  for  example,  is  — 118.8°  C.  (  — 182°  F.), 
while  that  of  nitrogen  is  —146°  C.  (—230°  F.).  The  critical 
pressures  are  50.8  and  35  atmospheres  respectively.  As  there 
is  no  difficulty  in  obtaining  these  pressures,  the  problem  of 
liquefying  oxygen  and  nitrogen  and  air  resolves  itself  into  find- 
ing a  method  of  producing  temperatures  below  the  critical  tem- 
peratures of  these  gases. 

It  is  well  known  that  a  temperature  somewhat  below  the 
freezing  point  of  water  can  be  produced  artificially  by  mixing 
ice  and  salt.  The  ordinary  ice-cream  freezer  is  a  familiar  appli- 
cation of  this  method  of  producing  cold.  Other  freezing  mix- 
tures that  are  sometimes  used  consist  of  calcium  chloride  and 
snow,  that  gives  the  temperature  —48°  C.  (  —  54.4°  F.),  and 
solid  carbonic  acid  and  ether,  that  is  capable  of  lowering  the 
temperature  to  — 100°  C.  (  — 148°  F.).  But  even  with  the  latter 
mixture  it  is  not  possible  to  reach  the  critical  temperature  of 
oxygen  or  that  of  nitrogen.  How,  then,  is  it  possible  to  reach 
these  extremely  low  temperatures  ? 

In  order  to  answer  this  question  it  will  be  necessary  to  take 
into  consideration  certain  temperature  changes  that  are  ob- 
served when  solids  are  melted  and  liquids  are  boiled,  as  well  as 
when  gases  are  liquefied  and  liquids  are  frozen.  When  heat  is 
21 


322  ACHIEVEMENTS  IN  SCIENCE 

applied  to  a  mass  of  ice  at  its  melting  point  it  melts  and  forms 
a  mass  of  water  having  the  same  temperature.  Heat  disap- 
pears in  the  operation.  It  is  stored  up  in  the  water.  This  dis- 
appearance of  heat  that  accompanies  the  melting  of  ice  can  be 
shown  in  a  very  striking  way  by  mixing  a  certain  weight  of  ice 
with  the  same  weight  of  water  that  has  been  heated  to  80°  C. 
(176°  F.).  The  ice  will  melt  and  all  the  water  obtained  will  be 
found  to  have  the  temperature  of  the  melting  ice — that  is,  o°  C. 
(32°  F.).  The  water  of  80°  C.  is  thus  cooled  down  to  o°  by 
the  melting  of  the  ice.  Again,  when  heat  is  applied  to  water 
its  temperature  rises  until  the  boiling  point  is  reached.  Then 
it  is  converted  into  vapor,  but  this  vapor  has  the  temperature 
of  the  boiling  water.  During  the  process  of  boiling  there  is  no 
rise  in  the  temperature  of  the  water  or  of  the  vapor.  Heat  dis- 
appears, therefore,  or  is  used  up  in  the  process  of  vaporization. 
Similar  phenomena  are  observed  whenever  a  solid  is  melted  or 
a  liquid  is  boiled.  When,  however,  a  gas  is  liquefied  it  gives 
up  again  the  heat  that  is  absorbed  by  it  when  it  is  formed  from 
a  liquid ;  and  so  also  when  a  liquid  solidifies  it  gives  up  the  heat 
it  absorbs  when  it  is  formed  from  a  solid. 

But  it  is  not  necessary  that  a  gas  should  be  converted  into 
a  liquid  in  order  that  it  should  give  up  heat.  Whenever  it  is 
compressed  it  becomes  warmer.  Some  of  the  heat  stored  up  in 
it  is,  as  it  were,  squeezed  out  of  it.  Conversely,  whenever  a  gas 
expands,  it  takes  up  heat  and,  of  course,  surrounding  objects 
from  which  the  heat  is  taken  become  colder.  Now,  it  is  a  com- 
paratively simple  matter  to  compress  air.  Every  wheelman 
knows  that,  and  he  also  knows  that  the  process  causes  a  rise 
in  temperature ;  at  least  he  knows  it  if  he  uses  a  small  hand 
pump.  With  large  pumps  run  by  steam  any  desired  pressure 
can  be  reached.  This  is  simply  a  question  of  securing  the 
proper  engines,  and  vessels  sufficiently  strong  to  stand  the 
pressure.  It  has  already  been  pointed  out  that  several  gases 
are  now  liquefied  on  the  large  scale  by  means  of  pressure.  It 
is  to  be  noted  that  low  temperatures  can  be  produced  by  con- 
verting certain  gases,  such  as  ammonia  and  carbonic  acid,  into 
liquids,  and  by  compressing  certain  gases,  as,  for  example,  air. 
When  liquefied  gases  are  used  it  is  only  necessary  to  allow 


CHEMISTEY  323 

them  to  pass  rapidly  into  the  gaseous  state,  when  more  or  less 
heat  is  absorbed.  This  is  the  basis  for  the  use  of  liquid  ammo- 
nia in  the  manufacture  of  ice.  A  vessel  containing  the  liquid 
ammonia  is  placed  in  another  containing  water.  The  inner 
vessel  being  opened,  the  liquid  ammonia  is  rapidly  converted 
into  the  gas;  heat  is  absorbed  from  the  water;  it  freezes. 
When  a  vessel  containing  liquid  carbonic  acid  is  opened  so  that 
the  gas  that  is  formed  escapes  through  a  small  valve,  so  much 
heat  is  absorbed  that  a  part  of  the  liquid  carbonic  acid  is  itself 
frozen.  In  this  case  the  substance  is  present  in  all  three  states 
of  aggregation — the  solid,  the  liquid,  and  the  gaseous.  The  use 
of  a  mixture  of  ether  and  solid  carbonic  acid  as  a  feezing  mixs- 
ture  has  already  been  referred  to.  Its  value  depends,  of  course, 
principally  upon  the  fact  that  solid  carbonic  acid  is  liquefied, 
and  the  liquid  then  converted  into  gas,  both  of  which  operations 
involve  absorption  of  heat. 

We  are  now  prepared  to  understand  the  important  experi- 
ments of  Cailletet  and  of  Pictet,  the  results  of  which  were  pub- 
lished in  1877.  It  should  be  said  that  they  worked  indepen- 
dently of  each  other — Cailletet  in  Paris  and  Pictet  in  Geneva. 
Pictet  liquefied  carbonic  acid  and  sulphur  dioxide  by  pressure. 
The  liquid  carbonic  acid  was  passed  through  a  tube  that  was 
surrounded  by  liquid  sulphur  dioxide  boiling  in  a  partial  vacuum. 
The  liquid  carbonic  acid  thus  cooled  was  then  boiled  under 
diminished  pressure  in  a  jacket  surrounding  a  tube  in  which 
the  gas  to  be  liquefied  was  contained  under  high  pressure. 
When  -this  gas  was  allowed  to  escape  from  a  small  opening  its 
temperature  was  so  reduced  by  the  expansion  that  a  part  of  it 
was  liquefied  in  the  tube  and  passed  off  as  a  liquid.  Cailletet 
worked  in  essentially  the  same  way,  but  on  a  smaller  scale. 
Neither  of  these  experimenters  liquefied  oxygen  or  nitrogen  on 
the  large  scale,  but  they  pointed  out  the  way  that  must  be  fol- 
lowed in  order  that  success  may  be  attained.  They  destroyed 
the  belief  in  "  permanent "  gases. 

Later  experimenters  in  this  field  are  Wroblewski,  Olszewski, 
and  Dewar,  who  have  been  interested  mainly  in  the  purely  sci- 
entific side  of  the  problem,  while  Linde  in  Germany,  Hampson 
in  England,  and  Tripler  in  the  United  States  have  their  minds 


324  ACHIEVEMENTS  IN  SCIENCE 

on  the  practical  side.  Notwithstanding  the  low  temperatures 
involved  in  the  experiments,  a  number  of  heated  discussions 
have  been  carried  on  in  the  scientific  journals  touching  the 
question  of  priority.  To  the  unprejudiced  observer  it  appears 
that  all  of  those  named  above  are  entitled  to  credit.  They  have 
all  helped  the  cause  along,  but  just  how  to  apportion  the  credit 
no  one  knows.  In  a  general  way,  however,  some  of  the  results 
obtained  by  each  in  turn  should  be  given.  Wroblewski  and 
Olszewski  have  carried  on  the  work  begun  by  Cailletet  and 
Pictet,  and  have  produced  lower  temperatures. 

In  the  latest  form  of  apparatus  used  by  Olszewski,  liquid 
ethylene  is  used  as  the  cooling  agent.  Its  boiling  point  is 
—  102°  C.  (  —  151.6°  F.).  By  causing  it  to  boil  rapidly  under 
diminished  pressure  a  temperature  below  the  critical  tempera- 
ture of  oxygen  can  be  reached.  As  early  as  1891,  Olszewski 
obtained  as  much  as  two  hundred  cubic  centimeters  of  liquid 
air  by  this  method.  Dewar  has  also  made  use  of  liquid  ethy- 
lene. This  was  passed  through  a  spiral  copper  tube  surrounded 
by  solid  carbonic  acid  and  ether.  It  was  then  passed  into  a 
cylinder  surrounded  by  another  cylinder  containing  solid  car- 
bonic acid  and  ether.  A  spiral  copper  tube,  which  runs  through 
the  outer  cylinder  and  also  through  the  inner  cylinder  in  which 
the  ethylene  was  boiling  under  diminished  pressure,  carried  the 
air.  This  was  liquefied  and  then  collected  in  a  vacuum  vessel 
below.  Later  he  found  that  air  can  be  liquefied  by  using  liquid 
carbonic  acid  alone  as  the  cooling  agent.  As  he  remarks: 
"  With  this  simple  machine,  one  hundred  cubic  centimeters  of 
liquid  oxygen  can  readily  be  obtained,  the  cooling  agent  being 
carbon  dioxide,  at  the  temperature  of  —79°.  If  liquid  air  has 
to  be  made  by  this  apparatus,  then  the  carbonic  acid  must  be 
kept  under  exhaustion  of  about  one  inch  of  mercury  pressure, 
so  as  to  begin  with  a  temperature  of  —115°." 

The  introduction  of  the  vacuum  vessel  by  Dewar  has  been 
of  great  service  in  all  the  work  on  liquefied  gases.  A  vacuum 
vessel  is  a  double-walled  glass  vessel.  The  space  between 
the  inner  and  outer  walls  of  the  vessel  is  exhausted  by  means 
of  an  air  pump  before  it  is  closed.  The  vessel  is  therefore 
surrounded  by  a  vacuum.  As  heat  is  not  conducted  by  a 


CHEMISTRY 


325 


vacuum,  it  is  possible  to  keep  specimens  of  liquefied  gases 
in  such  vessels  for  a  surprisingly  long  time.  Heat  enough 
cannot  pass  through  the  vacuum  to  vaporize  the  liquid  rap- 
idly. The  most  common  form  of  these  vessels  is  that  of  a 
globe.  Such  a  vessel  is  known  as  a  Dewar  globe  or  bulb. 

It  has  been  found  that  liquid  air  can  be  kept  very  well  by 
putting  it  in  a  tin  or  galvanized  iron  vessel,  which  in  turn  is 
placed  in  a  larger  one,  and  then  filling  the  space  between  the 
two  with  felt.  Under  these  conditions  vaporization  takes  place 
quite  slowly,  and  it  is  possible  to  transport  the  liquid  compara- 
tively long  distances.  It  has,  for  example,  been  transported 
from  New  York  to  Baltimore  and  Washington.  In  one  case 
with  which  the  writer  is  familiar  two  cans  were  taken  from  Mr. 
Tripler's  laboratory  in  the  morning,  delivered  at  the  Johns 
Hopkins  University  in  the  afternoon,  and  used  to  illustrate  a 
lecture  in  the  evening.  After  the  lecture  there  was  enough 
left  for  certain  experiments  that  were  carried  on  during  the 
rest  of  the  night. 

Tripler,  Linde,  and  Hampson  have  all  succeeded  in  devising 
forms  of  apparatus  by  means  of  which  air  can  be  liquefied  with- 
out the  aid  of  other  cooling  agents  than  the  expanding  air.  In 
principle  the  methods  employed  by  these  three  workers  are 
essentially  the  same.  It  appears  from  the  published  statements 
that  at  the  present  time  Tripler's  plant  is  the  most  efficient. 
While  a  few  years  ago  a  half  pint  or  so  of  liquid  air  is  said  to 
have  cost  $500,  now  five  gallons  can  be  made  for  about  $20, 
and  probably  much  less.  The  general  working  of  Tripler's 
apparatus  is  as  follows.  Given  three  steam  compression 
pumps.  Air  is  taken  from  above  the  roof  of  the  laboratory. 
In  the  first  pump  it  is  compressed  to  sixty-five  pounds  to 
the  square  inch.  It,  of  course,  becomes  heated  as  it  is  com- 
pressed. In  order  to  cool  it  down  again  it  is  passed  through  a 
coil  connecting  the  first  and  second  pumps,  which  is  surround- 
ed by  water  of  the  ordinary  temperature.  This  compressed 
and  cooled  air  is  then  further  compressed  in  the  second  pump 
to  four  hundred  pounds  to  the  square  inch.  Again  it  is  cooled 
in  the  same  way  as  before  by  means  of  water  which  circulates 
around  a  coil  connecting  the  second  and  third  pumps.  Once 


326  ACHIEVEMENTS  IN  SCIENCE 

more  the  air  is  compressed  this  time  in  the  third  pump,  in 
which  it  is  subjected  to  a  pressure  of  2,000  to  2,500  pounds 
to  the  square  inch ;  and  then  this  compressed  air  is  brought 
down  to  the  ordinary  temperature  in  a  cooler  consisting  of  a  coil 
similar  to  those  connecting  the  pumps.  The  air  under  this 
great  pressure  is  now  passed  through  a  purifier  where  it  is 
freed  from  particles  of  dust  and  to  a  great  extent  from  moist- 
ure. From  the  purifier  the  air  passes  into  an  inner  bent  tube, 
about  thirty  feet  in  length,  at  the  end  of  which,  the  critical 
point  of  the  apparatus,  is  situated  a  needle  valve  from  which 
the  air  is  allowed  to  escape.  It,  of  course,  expands  enormously, 
and  is  correspondingly  cooled.  This  very  cold  air  passes  into 
the  space  between  the  inner  and  outer  tubes,  and  finally  escapes 
at  a  vent  at  the  other  end  of  the  bent  tube.  The  result  of  this 
is  that  the  compressed  air  in  the  inner  tube  is  soon  cooled 
down  so  far  that  a  considerable  part  of  the  air  that  escapes 
at  the  needle  valve  appears  in  the  liquid  form.  This  collects 
in  the  lower  part  of  the  jacket,  and  on  opening  the  stopcock  un- 
derneath the  liquid  escapes  in  a  stream  the  size  of  one's  finger. 

In  Mr.  Tripler's  laboratory  the  liquid  is  collected  in  the 
cans  already  referred  to.  Although  for  the  reasons  mentioned 
the  evaporation  of  the  liquid  is  comparatively  slow,  it  is  con- 
stantly going  on,  and  as  the  gas  formed  occupies  a  very  much 
larger  volume  under  the  pressure  of  the  atmosphere  than  the 
liquid  from  which  it  is  formed,  it  is  necessary  to  leave  the  cans 
loosely  covered.  Otherwise  the  pressure  would  increase  to 
such  an  extent  as  to  burst  any  but  the  strongest  vessels.  One 
cubic  foot  of  liquid  air  gives  at  atmospheric  pressure  eight 
hundred  cubic  feet  of  gaseous  air. 

Liquid  air  obtained  as  described  is  a  turbid,  colorless  liquid. 
The  turbidity  is  due  to  the  presence  of  solid  water  and  solid 
carbonic  acid.  By  passing  the  liquid  through  a  paper  filter  the 
solids  are  removed,  and  a  transparent  liquid  is  thus  obtained. 
This,  as  already  stated,  consists  mostly  of  nitrogen  and  oxygen 
in  the  proportion  of  about  four -fifths  of  the  former  to  one-fifth 
of  the  latter.  Though  it  should  not  be  forgotten  that  this 
liquid  contains  argon  in  small  quantity,  besides  three  or  four 
other  substances  in  still  smaller  quantities,  as  has  recently  been 


CHEMISTRY  327 

shown  by  Professor  Ramsay,  we  may  disregard  everything 
except  the  nitrogen  and  oxygen.  Liquid  air  is  a  mixture  si 
these  two  substances.  They  are  not  chemically  combined  as 
hydrogen  and  oxygen  are,  for  example,  in  water.  This  mixture 
boils  at  —191°  C  (  —  312°  F.),  which  is  the  temperature  of  the 
liquid  as  it  is  in  the  cans.  As  the  nitrogen  boils  at  a  lower 
temperature  (—194°  C.  or  318°  F.)  than  oxygen  (  —  183°  C.  or 
297°  F.),  more  nitrogen  is  converted  into  gas  in  a  given  time 
than  oxygen,  and  after  a  time  the  liquid  that  is  left  is  much 
richer  in  oxygen  than  ordinary  air.  When  liquid  air  is  poured 
upon  water,  it,  being  a  little  lighter  than  the  water,  floats,  not 
quietly,  to  be  sure,  but  in  a  very  troubled  way.  Soon,  however, 
the  liquid  sinks  to  the  bottom  because  the  nitrogen,  which  is 
the  lighter  constituent,  passes  into  the  gaseous  state,  and  the 
liquid  oxygen  which  is  left  is  a  little  heavier  than  water.  The 
experiment  is  a  very  beautiful  one.  A  scientific  poet  could 
alone  do  justice  to  it.  The  beauty  is  enhanced  by  the  fact  that 
while  liquid  air  is  colorless,  or  practically  so,  liquid  oxygen  is 
distinctly  blue. 

Although  liquid  air  has  the  temperature  —191°  C.  (  —  312° 
F.),  one  can  without  danger  pass  the  hand  through  it  rapidly. 
The  sensation  is  a  new  one,  but  it  is  evanescent.  Very  serious 
results  would  follow  if  the  hand  were  allowed  to  remain  in  the 
liquid  even  for  a  short  time.  The  tissues  would  be  killed.  So 
also,  it  is  possible  to  pass  the  hand  rapidly  through  molten  lead 
without  injury.  In  the  latter  case  the  moisture  on  the  hand  is 
converted  into  vapor  which  forms  a  protecting  cushion  between 
the  hand  and  the  hot  liquid ;  while,  in  the  former  case,  the  heat 
of  the  hand  converts  the  liquid  air  immediately  surrounding  it 
into  gas  which  prevents  the  liquid  from  coming  in  contact  with 
the  hand. 

When  the  liquid  is  poured  out  of  a  vessel  in  the  air  it  is 
rapidly  converted  into  gas.  The  great  lowering  in  the  tempera- 
ture causes  a  condensation  of  the  moisture  of  the  air  in  the 
form  of  a  cloud.  The  same  thing  is  seen  when  the  cover  is  re- 
moved from  a  can  containing  the  liquid.  Of  course,  this  liquid 
does  not  wet  things  as  water  does.  When,  however,  as  hap- 
pened in  New  York,  the  lecturer  deliberately  pours  a  dipperful 


328  ACHIEVEMENTS  IN  SCIENCE 

of  the  liquid  upon  a  priceless  Worth  gown,  he  may  expect  to 
hear  expressions  of  horror  from  the  owner.  This  experiment 
passed  off  most  successfully.  Every  trace  of  the  liquid  air  was 
converted  into  invisible  gases  before  the  fleeting  agony  of  the 
sympathetic  audience  had  passed  away. 

The  effects  of  very  low  temperature  upon  a  number  of  sub- 
stances have  been  studied,  and  some  of  them  can  easily  be 
shown.  Paraffin,  resin,  and  rubber  immersed  in  liquid  air  soon 
become  very  brittle,  and  the  color  of  the  resin  is  completely 
changed.  A  beefsteak  or  an  onion  also  becomes  brittle,  and 
can  be  broken  into  small  fragments  by  the  blow  of  a  hammer. 
A  similar  effect  is  produced  in  the  case  of  some  metals.  Tin 
and  iron,  for  example,  become  brittle,  and  the  tenacity  of  the 
iron  is  greatly  increased.  A  copper  wire,  however,  retains  its 
flexibility.  At  low  temperatures  the  electric  conductivity  of 
all  metals  is  increased.  In  general,  the  lower  the  temperature 
the  greater  the  conductivity.  If  a  copper  wire  could  by  any 
means  be  kept  cold  enough,  electrical  energy  could  be  trans- 
mitted by  it  with  but  little  loss — perhaps  none.  Mercury  is 
easily  frozen  by  surrounding  it  with  liquid  air,  and  the  solid 
thus  formed  is  very  hard,  though  if  it  is  cooled  down  sufficiently 
it  becomes  brittle. 

Alcohol  can  be  frozen  without  difficulty  by  means  of  liquid 
air.  By  the  aid  of  the  lowest  temperatures  hitherto  attainable 
it  has  only  been  possible  to  convert  alcohol  into  a  pasty  mass. 
The  frozen  alcohol  is  as  hard  as  ice.  When  alcohol  is  dropped 
into  liquid  air  the  drops  retain  the  globular  form.  When  taken 
out  on  a  platinum  loop  the  flame  of  a  Bunsen  burner  does  not 
set  fire  to  it. 

Phosphorescence  is  greatly  increased  by  cooling  substances 
down  to  the  temperature  of  liquid  air.  This  has  been  shown 
by  means  of  water,  milk,  paper,  eggs,  and  feathers.  An  egg 
and  a  feather  could  be  distinctly  seen  in  a  dark  room. 

Scarlet  iodide  of  mercury  is  converted  into  the  yellow  variety 
when  it  is  subjected  to  the  temperature  of  liquid  air.  Some 
other  colors  are  changed  under  the  same  circumstances,  but 
not  enough  is  known  of  this  subject  to  warrant  a  general  state- 
ment. 


CHEMISTRY  329 

Attention  has  already  been  called  to  the  fact  that  liquid  air 
loses  its  nitrogen  more  rapidly  than  it  does  its  oxygen,  and 
that,  after  a  time,  the  residue  contains  a  large  proportion  of 
oxygen.  As  combustion  is  combination  with  oxygen,  combus- 
tion or  burning  takes  place  more  readily  in  contact  with  this 
liquid  oxygen  than  it  does  in  the  air.  If  a  lighted  match  is  at- 
tached to  the  end  of  a  steel  watch-spring,  and  this  then  plunged 
beneath  the  surface  of  liquid  air,  the  spring  will  soon  take  fire 
and  burn  brilliantly,  the  sparks  flying  off  for  some  distance  in 
beautiful  coruscations.  Hair  felt,  which  does  not  burn  in  the 
air,  burns  in  a  flash  when  soaked  with  liquid  air.  Finally, 
when  liquid  air  is  confined  in  any  vessel  not  capable  of  sustain- 
ing an  enormous  pressure,  say  about  10,000  pounds  to  the 
square  inch,  the  vaporization  goes  on  until  the  vessel  bursts  or 
the  stopper  is  forced  out.  It  might  therefore  be  used  as  an 
explosive  without  any  addition,  but  its  manipulation  is  not  alto- 
gether simple. 

Now  for  the  inevitable  question :  Of  what  use  is  liquid  air 
likely  to  be  ?  This  is  a  perfectly  proper  question,  and  yet  if 
scientific  workers  always  stopped  to  ask  it  and  would  not  work 
unless  they  could  find  a  favorable  answer,  progress  would,  to 
say  the  least,  be  much  slower  than  it  is.  Most  great  practical 
discoveries  have  necessarily  passed  through  the  plaything  stage. 
Some  of  the  most  important  discoveries  have  not  even  furnished 
playthings,  and  have  found  no  practical  applications  as  this  ex- 
pression is  commonly  understood.  But  the  production  of  liquid 
air,  while  furnishing  mankind  with  a  beautiful  and  instructive 
plaything,  seems  likely  to  find  practical  applications.  We  may 
look  for  these  in  four  directions,  to  each  of  which  a  short  para- 
graph may  be  devoted : 

First,  as  a  cooling  agent.  Low  temperature  is  marketable. 
To  be  sure,  the  demand  for  the  extremely  low  temperature  that 
can  be  produced  by  liquid  air  does  not  exist  to-day,  but  this 
concentrated  low  temperature  can  be  diluted  to  suit  conditions. 
The  only  question  to  be  answered  in  this  connection  is  then, 
What  is  the  cost  of  cold  produced  by  liquid  air  ?  It  is  impos- 
sible for  any  one  to  answer  this  question  at  all  satisfactorily  at 
present.  It  can  only  be  said  that  this  is  what  experimenters 


330  ACHIEVEMENTS  IN  SCIENCE 

are  trying  to  find  out.  It  appears,  however,  that  they  are  on 
the  way  to  cheap  liquid  air,  and  that  as  the  processes  are  im- 
proved the  price  will  become  lower  and  lower. 

Second,  for  the  construction  of  motors.  There  is  no  doubt 
that  liquid  air  with  its  enormous  power  of  expansion  can  be 
used  as  a  source  of  motive  power  just  as  compressed  air  is.  In 
the  case  of  steam  it  is  necessary  to  heat  the  water  in  order  to 
convert  it  into  steam,  and  to  heat  the  steam  to  give  it  the  power 
of  expansion.  The  cost  is,  in  the  first  instance,  that  of  the 
fuel.  Given  a  certain  amount  of  heat,  and  a  certain  amount  of 
work  is  obtained.  If  liquid  air  is  used,  the  problem  is  much 
the  same.  Engines  must  be  run  in  order  to  compress  the  air 
which  is  to  be  liquefied.  Every  gallon  of  liquid  air  has  been 
produced  at  the  expense  of  work  of  some  kind.  Now,  the 
question  arises  at  once,  What  proportion  of  the  work  that  was 
put  in  that  gallon  of  liquid  air  in  the  course  of  its  production 
can  be  got  out  of  it  again  ?  It  is  certain  that  all  of  it  cannot  be 
got  out  unless  all  that  we  have  ever  learned  about  such  matters 
goes  for  nothing.  In  dealing  with  the  problem  of  the  applica- 
tion of  liquid  air  as  a  source  of  motive  power  we  are  therefore 
doubly  handicapped.  In  the  first  place,  we  do  not  know  the 
cost  of  the  liquid  when  produced  on  the  large  scale ;  and,  in  the 
second  place,  we  do  not  know  the  probable  efficiency  of  a  liquid- 
air  motor.  I  say  "  we  do  not  know."  Perhaps  Mr.  Tripler  and 
the  others  engaged  in  the  experiments  on  this  subject  do  know 
approximately.  We  certainly  cannot  blame  them  for  not  tell- 
ing us  all  they  know  at  this  stage  of  the  work.  It  is  unfortu- 
nate, however,  that  such  a  statement  as  was  recently  published 
in  a  popular  magazine  should  be  allowed  to  gain  currency— 
apparently  with  the  sanction  of  Mr.  Tripler.  The  statement 
referred  to  is  to  the  effect  that  ten  gallons  of  liquid  air  have 
been  made  by  the  use  of  three  gallons  of  liquid  air  in  the 
engine.  If  that  means  that  the  ten  gallons  of  liquid  air  are 
made  from  air  at  the  ordinary  pressure,  the  statement  is  in 
direct  conflict  with  well-established  principles.  If  it  means 
that  the  ten  gallons  of  liquid  air  are  made  from  air  that  has 
already  been  partly  compressed,  we  must  know  how  much  work 
has  been  done  before  the  liquid-air  engine  began.  Leaving 


CHEMISTRY  331 

out  of  consideration  the  question  of  cost,  it  may  be  pointed  out 
that  liquid-air  engines  would  have  the  advantage  of  compact- 
ness, though  they  would  necessarily  be  heavy,  as  they  would 
have  to  be  strong  enough  to  stand  the  great  pressure  to  which 
they  would  be  subjected. 

The  third  application  of  liquid  air  that  has  been  suggested 
is  in  the  preparation  of  an  explosive.  In  fact,  an  explosive  has 
been  made  and  used  for  some  time  in  which  liquid  air  is  one  of 
the  constituents.  When  the  liquid  from  which  a  part  of  the 
nitrogen  has  boiled  off  is  mixed  with  powdered  charcoal,  the 
mixture  burns  with  great  rapidity  and  great  explosive  force. 
"  To  make  this  explosive,  Dr.  Linde  pours  the  liquid  containing 
about  forty  or  fifty  per  cent  of  oxygen  on  fragments  of  wood 
charcoal,  two  or  four  cubic  millimeters  in  size.  These  are  kept 
from  scattering  under  the  ebullition  of  the  liquid  by  mixing 
them  into  a  sort  of  sponge  with  about  one-third  of  their  weight 
of  cotton  wool."  Of  course,  this  explosive  must  be  made  at  or 
near  the  place  where  it  is  used.  It  has  been  in  use  in  the  way 
of  a  practical  test  in  a  coal  mine  at  Pensberg,  near  Munich.  It 
is  claimed  that  the  results  were  satisfactory.  The  chief  advan- 
tage of  the  explosive  js  its  cheapness,  and  the  fact  that  it  soon 
loses  its  power  of  exploding. 

Finally,  the  fourth  application  of  liquid  air  is  for  the  pur- 
pose of  getting  oxygen  from  the  air.  This  can  be  accomplished 
by  chemical  means,  but  the  chemical  method  is  somewhat  ex- 
pensive. Oxygen  has  commercial  value,  and  cheap  oxygen 
would  be  a  decided  advantage  in  a  number  of  branches  of  in- 
dustry. It  will  be  observed  that  it  is  the  liquid  oxygen  that 
makes  possible  the  preparation  of  the  explosive  described  in  the 
last  paragraph.  Oxygen,  as  such,  in  the  form  of  gas  is  of  value 
in  Deacon's  process  for  the  manufacture  of  chlorine.  In  this 
process  air  and  hydrochloric  acid  are  caused  to  act  upon  each 
other  so  as  to  form  water  and  chlorine.  The  nitrogen  takes  no 
part  in  the  act,  and  it  would  be  an  advantage  if  it  could  be  left 
out.  It  is  only  the  oxygen  that  is  wanted.  There  are  many 
other  possible  uses  for  oxygen  either  in  the  liquid  or  in  the 
gaseous  form,  but  these  need  no  mention  here. 

In  conclusion  it  may  safely  be  said  that  it  is  highly  probable 


332  ACHIEVEMENTS  IN  SCIENCE 

that  liquid  air  will  be  found  to  be  a  useful  substance,  but  it  is 
impossible  at  present  to  speak  with  any  confidence  of  the  par- 
ticular uses  that  will  be  made  of  it.  As  work  with  it  is  being 
carried  on  energetically  in  at  least  three  countries,  we  may  con- 
fidently expect  important  developments  in  the  near  future. 


CHEMISTRY 
The   Potter's  Art 

By  MARTHA  WASHINGTON  LEVY 

THE  progressive  steps  in  the  development  of  almost  every 
art  may  be  traced  by  examining  the  art  as  practiced  by 
peoples  of  different  stages  of  culture.  With  pottery,  however, 
this  is  difficult,  since  there  is  only  very  meager  information  re- 
lating to  it  among  uncivilized  peoples,  and  few  facts  are  recorded 
concerning  the  materials  used  and  the  methods  followed  in  its 
production. 

Since  the  art  was  intimately  connected  with  the  securing 
id  preparing  of  food,  it  belonged,  the  world  over,  among  sav- 
tribes  of  a  certain  state  of  culture,  to  women. 
It  is  probable  that  the  first  fire  kindled  on  clay  soil  baked 
the  clay  and  suggested  to  the  builder  of  the  fire  the  possibility 
)f  converting  a  soft  and  easily  molded  substance  into  a  hard 
id  permanent  article  of  use.     But  who  the  first  potter  was,  or 
rhere  he.worked,  is  unknown. 

Like  all  arts,  pottery  was  probably  the  result  of  a  long  de- 
ilopment.  But,  after  taking  root,  it  flourished  in  proportion 
to  the  advance  in  culture  of  the  people  itself,  so  that  to-day  it 
exists  in  all  stages  of  development,  from  the  coarse  ware  of 
the  savage  to  the  fine  porcelain  of  Sevres. 

The  earliest  examples  of  pottery  belong  to  the  Stone 
Age  and  bear  all  the  characteristics  of  a  primitive  period.  The 
material  of  which  they  are  composed  is  coarse,  while  the  objects 
themselves,  made  by  hand  without  the  potter's  wheel,  are  crude 
in  form  and  seem  to  have  been  imperfectly  hardened  in  an 
open  fire.  The  jars  are  frequently  cylindrical  in  form — though 

333 


334  ACHIEVEMENTS  IN  SCIENCE 

some  are  found  that  are  rounded  at  the  base  and  without  feet. 
Ornamentation  is  confined  to  simple,  incised  lines  produced  by 
the  impression  of  the  finger-nail,  or  by  a  cord  wound  around 
the  moist  clay.  Most  of  the  urns  of  this  period  are  sun-baked. 

In  the  Bronze  Age,  while  most  of  the  pottery  was  still  made 
by  hand,  it  was  wrought  more  skillfully,  and  in  some  instances 
shows  marks  of  the  potter's  wheel.  The  forms,  too,  were  more 
varied,  and  circles  and  figures  cut  in  bronze  were  introduced  as 
ornaments. 

Egypt  furnishes  the  earliest  examples  of  pottery  of  a  more 
advanced  period,  the  oldest  being  the  sun-dried  bricks  of  which 
some  of  the  pyramids  are  made.  These  occur  in  the  pyra- 
mid of  Sakkara,  dating  from  the  reign  of  Ouennephes,  about 
5000  B.C. 

That  they  had  the  potter's  wheel  from  an  early  period  is 
shown  in  the  painting  on  the  wall  of  one  of  the  tombs  at  Beni- 
Hassan,  dating  not  far  from  the  pyramid  of  Shoo-fou.  From 
this  it  is  evident  that  the  art  of  forming  circular  objects  has 
hardly  been  improved  in  4000  years :  then,  as  now,  the  lump 
of  clay  was  thrown  on  the  wheel  to  be  shaped  by  the  hands  or 
fingers. 

The  Egyptians  produced  two  varieties  of  pottery.  The 
first — the  ordinary,  soft  pottery — was  used  largely  for  vases, 
which  were  made  into  a  variety  of  forms,  and  employed  chiefly 
for  domestic  purposes  or  cinerary  urns.  But  their  highest  art 
was  displayed  in  the  use  of  the  enameled  pottery,  which  they 
were  the  first  to  produce.  This  was  usually  employed  in 
smaller  articles  and  for  inlaying  in  ornamental  work. 

From  Egypt,  the  art  is  supposed  to  have  passed  to  Nineveh 
and  Babylon,  where  it  was  applied  to  the  building  of  great  walls 
of  enameled  brick.  These  colored  bricks  were  formed  in  a 
wooden  or  terra-cotta  mold,  and  many  of  them  were  impressed, 
while  still  soft,  with  elaborate  cuneiform  characters,  serving 
thus  to  record  the  victories  of  the  kings. 

The  finest  objects  in  rude  clay  were  produced  by  the  ancient 
Greeks,  whose  most  primitive  productions,  though  dating  from 
almost  the  heroic  age,  reveal  a  remarkable  power  of  invention. 
Most  of  the  vases  were  made  of  a  fine,  sun-dried  clay,  decorated 


CHEMISTRY  335 

with  black  and  coated  with  glaze.  Though  some  were  made 
by  hand,  the  potter's  wheel  was  used  at  an  early  date. 

At  first  no  effort  at  pictorial  ornamentation  was  made,  the 
only  attempt  at  decoration  being  to  cover  the  clay  with  interlac- 
ing lines.  Later,  birds,  animals,  and  finally  the  human  figure 
were  introduced. 

In  Rome,  pottery  was  extensively  produced,  and  consisted 
largely  of  tiles,  bowls,  cinerary  urns,  and  low  boat-shaped  lamps. 
The  latter,  though  beautifully  embossed,  were  made  of  coarse 
clay  which  was  pressed,  while  soft,  into  melds.  Later  the  Ro- 
mans adopted  a  black,  glazed  surface,  but  in  this  never  attained 
the  perfection  achieved  by  the  Greeks.  The  best-known  Ro- 
man pottery  was  the  so-called  Samian  ware,  bright  red  in  color 
and  molded  in  relief  on  the  exterior. 

MODERN  POTTERY. 

The  process  by  which  the  present-day  pottery  is  manufac" 
tured  may  be  interesting  to  the  reader.  The  rude  clay  is 
ground  in  a  circular  pan — the  bottom  of  which  is  covered  with 
a  hard  stone — and,  after  having  been  run  into  a  large  vat,  is 
passed  through  several  sieves  of  varying  fineness.  It  is  then 
ready  to  have  the  moisture  eliminated,  and  for  this  purpose  is 
pumped  under  high  pressure  into  clay  presses.  Finally,  after 
having  been  cut  off  into  blocks,  the  clay  is  ready  for  use. 

In  studying  the  process  by  which  the  clay  is  converted  into 
the  various  articles  with  which  we  are  familiar,  we  visit  first 
the  thrower,  who,  after  throwing  a  ball  of  clay  on  the  wheel 
while  it  is  revolving,  seizes  it  and,  by  manipulation  alone,  con- 
torts the  clay  until  it  has  assumed  the  shape  he  requires.  The 
wheel  itself,  while  sometimes  worked  by  steam  power,  can  still 
be  seen  operated  by  hand  labor  as  practiced  by  the  potters  of 
antiquity. 

After  being  allowed  to  dry  to  a  certain  consistency,  the 
article  formed  by  the  thrower  is  placed  on  a  circular  piece  of 
wood,  where  all  superfluous  clay  is  removed,  and  it  is  thus 
given  the  proper  shape  and  finish.  When  handles  or  spouts 
are  required,  they  are  made  in  molds  and  attached  to  the 


336  ACHIEVEMENTS  IN  SCIENCE 

articles  with  water.  Flat  articles  such  as  plates,  and  hollow- 
wares  such  as  soup  tureens,  are  produced  by  beating  out  the 
clay  on  a  suitable  bat,  smoothing  its  surface,  and  then  pressing 
it  into  plaster  of  Paris  molds.  When  the  clay  hardens,  it  is 
easily  removed,  and  when  quite  dry  is  ready  for  the  oven. 

Another  mode  of  producing  articles  of  pottery  is  by  casting. 
In  this  case,  the  plaster  molds  are  filled,  not  with  clay,  but 
with  the  material,  in  a  "  slip  "  or  liquid  state.  Owing  to  the 
suction  of  the  plaster,  a  coating  of  clay  adheres  to  the  inner 
surface,  and  this  is  filled  up  until  the  desired  thickness  is 
obtained,  when  the  surplus  part  is  returned  to  the  tub.  Many 
useful  articles  such  as  cups,  jugs,  etc.,  are  produced  in  this  way. 

Pottery  ware  in  both  the  clay  and  biscuit  state  has  to  be 
fired  in  "  saggars  "  or  pans  made  of  fire-clay.  For  china  firing 
the  ware  is  embedded  in  fine-ground  flint,  but  earthenware  is 
placed  in  clean  sand,  which  prevents  the  articles  from  fusing 
together  under  the  intense  heat  to  which  they  are  subjected. 

The  biscuit  oven,  which  is  the  oven  in  which  the  ware  re- 
ceives its  first  fire,  is  cylindrical  in  form,  with  walls  made  of 
the  hardest  fire-brick,  built  fully  two  feet  thick,  and  pierced  at 
regular  intervals  by  fire-places  which  open  into  the  interior. 
The  floor  of  the  kiln  is  hollow,  and  over  an  opening  in  the  cen- 
ter is  a  column  of  rings  which  carry  the  flame  up  the  center,  so 
that  the  whole  oven  is  filled  with  flame. 

After  the  saggars  have  been  carried  to  the  ovens,  where 
they  are  piled  up  in  tall  columns  until  the  entire  space  is  filled, 
the  doorway  is  bricked  up  and  plastered  over,  and  it  is  now 
ready  to  fire.  Meanwhile,  a  pile  of  coals  has  been  ignited  out- 
side, and  the  fire  is  started  at  all  the  fire-holes  simultaneously. 

When  the  ware  is  drawn  from  the  oven  it  is  taken  to  the 
warehouse,  where  it  is  carefully  examined  to  discover  any  de- 
fects that  have  developed  in  firing,  the  defective  pieces  being 
rejected,  while  the  others  are  stored  ready  for  decoration. 

DECORATIONS 

Printing  is  one  of  the  most  popular  modes  for  decorating 
pottery.  The  patterns  are  engraved  upon  suitably  prepared 


A    GRECIAN     POTTER 

Irrom  a  painting  by  Paul  Thumann. 


CHEMISTRY  337 

copper,  which  the  workman,  when  about  to  take  off  a  print,  places 
upon  a  hot  stove  and  covers  with  a  thick  dab  of  color :  this  he 
works  into  every  part  of  the  pattern,  removes  the  surplus, 
and  leaves  the  color  only  in  the  incised  lines  in  the  copper. 
He  then  saturates  a  piece  of  prepared  tissue-paper  with  a  solu- 
tion of  soft  soap  and  water,  places  it  upon  the  copper  which 
has  been  removed  quite  warm  to  the  press,  and  after  the  roller 
of  this  has  revolved  upon  it,  the  engraving  is  again  placed  on 
the  stove  and  the  impression  removed  from  the  copper.  The 
surplus  paper  having  been  cut  away,  the  impression  is  rubbed 
upon  the  piece  of  ware  under  great  pressure.  The  paper  is 
then  washed  away  without  interfering  with  the  print,  and  the 
ware  is  taken  to  the  "  hardening-on  "  kiln,  where  it  is  fired  for 
about  nine  hours,  in  order  that  the  thick  oil  may  be  burned  out 
of  the  color,  and  the  ware  be  thus  made  ready  to  receive  the 
glaze. 

The  materials  forming  the  glaze  are  fired  in  a  special  kiln 
and  afterward  mixed  with  other  materials  which  are  ground  in 
water  in  the  mill  for  about  a  week.  After  having  been  dipped 
into  this  glaze,  which  spreads  itself  as  a  thin  glassy  coating 
over  the  whole  surface  of  the  article,  the  latter  is  taken  to  the 
glazing  oven,  where  it  is  packed  in  saggars  similar  to  those  of 
the  biscuit  oven.  From  there  the  printed  ware  is  removed  to 
the  warehouse,  and  that  requiring  further  decoration  is  passed 
to  the  enameling  department.  Here  the  workers  —  chiefly 
women — fill  up  the  printed  outline  which  the  ware  has  already 
received,  with  colors,  in  accordance  with  the  design  placed  be- 
fore them. 

Another  form  of  decoration  found  in  many  china  patterns 
is  the  addition  of  a  border  or  coating  all  over  the  surface  in 
various  colors.  This  is  produced  by  ground  laying,  a  process 
consisting  of  giving  the  ware  a  coating  of  adhesive  oil,  upon 
which  the  color  in  the  form  of  dust  is  dabbed  upon  the  surface. 

In  the  gilding  department,  gold  lines  are  added  to  the  ware, 
by  placing  the  article  on  a  revolving  wheel,  which  is  set  in  mo- 
tion by  the  workman's  hand,  while  he  holds  the  edge  of  the 
article.  The  gold  used  is  the  finest  that  can  be  obtained,  be- 
cause any  alloy  would  impart  to  the  metal  an  inferior  color. 
22 


338 


ACHIEVEMENTS  IN  SCIENCE 


Finally  comes  painting  on  china :  the  highest  class  of  deco- 
ration for  pottery. 

All  articles  that  are  richly  decorated  with  gold  upon  various 
colored  grounds,  or  painted  upon  the  glaze,  have  to  be  fired  in 
the  enamel  kiln:  an  oblong,  box-like  structure  built  of  fire- 
bricks and  having  iron  doors.  Since  no  fire  whatever  pene- 
trates the  inside,  the  structure  is  very  unlike  an  oven,  and  is 
more  comparable  with  a  gigantic  saggar,  with  the  fire  playing 
around  it.  The  articles  are  not  enclosed  in  anything,  but  are 
arranged  upon  iron  bats  supported  by  short  iron  props,  tier 
above  tier.  Then  the  finished  article  goes  into  the  wareroom. 


EVOLUTION  AND  NATURE  STUDIES 


Origin  of  the  Darwinian  Theory 

By  ALFRED  RUSSEL  WALLACE 

WE  now  approach  the  subject  which,  in  popular  estimation, 
and  perhaps  in  real  importance,  may  be  held  to  be  the 
great  scientific  work  of  the  nineteenth  century — the  establish- 
ment of  the  general  theory  of  evolution,  by  means  of  the  special 
theory  of  the  development  of  the  organic  world  through  the 
struggle  for  existence  and  its  necessary  outcome,  Natural  Selec- 
tion. Although  in  the  last  century  Buff  on,  Dr.  Erasmus  Dar- 
win, and  the  poet  Goethe  had  put  forth  various  hints  and  sug- 
gestions pointing  to  evolution  in  the  organic  world,  which  they 
undoubtedly  believed  to  have  occurred,  no  definite  statement  of 
the  theory  had  appeared  till  early  in  the  present  century,  when 
La  Place  explained  his  views  as  to  the  evolution  of  the  stellar 
universe  and  of  solar  and  planetary  systems  in  his  celebrated 
Nebular  Hypothesis ;  and  about  the  same  time  Lamarck  pub- 
lished his  "Philosophic  Zoologique,"  containing  an  elaborate 
exposition  of  his  theory  of  the  progressive  development  of  ani- 
mals and  plants.  But  this  theory  gained  few  converts  among 
naturalists,  partly  because  Lamarck  was  before  his  time,  and 
also  because  the  causes  he  alleged  did  not  seem  adequate  to 
produce  the  wonderful  adaptations  we  everywhere  see  in  nature. 
During  the  first  half  of  the  present  century,  owing  to  the  fact 
that  Brazil,  South  Africa,  and  Australia  then  became  for  the 
first  time  accessible  to  English  collectors,  the  treasures  of  the 
whole  world  of  nature  were  poured  in  upon  us  so  rapidly  that 
the  comparatively  limited  number  of  naturalists  were  fully  occu- 
pied in  describing  the  new  species  and  endeavoring  to  discover 

339 


340  ACHIEVEMENTS  IN  SCIENCE 

true  methods  of  classification.  The  need  of  any  general  theory 
of  how  species  came  into  existence  was  hardly  felt ;  and  there 
was  a  general  impression  that  the  problem  was  at  that  time  in- 
soluble, and  that  we  must  spend  at  least  another  century  in  col- 
lecting, describing,  and  classifying,  before  we  had  any  chance 
of  dealing  successfully  with  the  origin  of  species.  But  the  sub- 
ject of  evolution  was  ever  present  to  the  more  philosophic 
thinkers,  though  the  great  majority  of  naturalists  and  men  of 
science  held  firmly  to  the  dogma  that  each  species  of  animal 
and  plant  was  a  distinct  creation,  though  how  produced  was  ad- 
mitted to  be  both  totally  unknown  and  almost,  if  not  quite, 
unimaginable. 

The  vague  ideas  of  those  who  favored  evolution  were  first 
set  forth  in  systematic  form,  with  much  literary  skill  and  scien- 
tific knowledge,  by  the  late  Robert  Chambers  in  1844,  in  his 
anonymous  volume,  "Vestiges  of  the  Natural  History  of  Crea- 
tion." He  passed  in  review  the  stellar  and  solar  systems, 
adopted  the  Nebular  Hypothesis,  and  sketched  out  the  geologi- 
cal history  of  the  earth,  with  continuous  progression  from  lower 
to  higher  forms  of  life.  After  describing  the  peculiarities  of 
the  lower  plants  and  animals,  dwelling  upon  those  features 
which  seemed  to  point  to  a  natural  mode  of  production  as 
opposed  to  an  origin  by  special  creation,  the  author  set  forth 
with  much  caution  the  doctrine  of  progressive  development  re- 
sulting from  "  an  impulse  which  was  imparted  to  the  forms  of 
life,  advancing  them  in  definite  lines,  by  generation,  through 
grades  of  organization  terminating  in  the  highest  plants  and 
animals."  The  reasonableness  of  this  view  was  urged  through 
the  rest  of  the  work ;  and  it  was  shown  how  much  better  it 
agreed  with  the  various  facts  of  nature  and  with  the  geographi- 
cal distribution  of  animals  and  plants,  than  the  idea  of  the 
special  creation  of  each  distinct  species. 

It  will  be  seen,  from  this  brief  outline,  that  there  was  no 
attempt  whatever  to  show  how  or  why  the  various  species  of 
animals  and  plants  acquire  their  peculiar  characters,  but  merely 
an  argument  in  favor  of  the  reasonableness  of  the  fact  of  pro- 
gressive development,  from  one  species  to  another,  through  the 
ordinary  processes  of  generation.  The  book  was  what  we 


EVOLUTION  AND  NATURE  STUDIES          341 

should  now  call  mild  in  the  extreme.  It  was  serious  and  even 
religious  in  tone,  and  calculated  in  this  respect  to  disarm  the 
opposition  even  of  the  most  orthodox  theologists ;  yet  it  was 
met  with  just  the  same  storm  of  opposition  and  indignant  abuse 
which  assailed  Darwin's  work  fifteen  years  later.  As  an  illus- 
tration of  the  state  of  scientific  opinion  at  this  time,  it  may  be 
mentioned  that  so  great  a  man  as  Sir  John  Herschel,  at  a  sci- 
entific meeting  in  London,  spoke  strongly  against  the  book  for 
its  advocacy  of  so  great  a  scientific  heresy  as  the  Theory  of 
Development. 

I  well  remember  the  excitement  caused  by  the  publication 
of  the  "Vestiges,"  and  the  eagerness  and  delight  with  which  I 
read  it.  Although  I  saw  that  it  really  offered  no  explanation 
of  the  process  of  change  of  species,  yet  the  view  that  the  change 
was  effected,  not  through  any  unimaginable  process,  but 
through  the  known  laws  and  processes  of  reproduction,  com- 
mended itself  to  me  as  perfectly  satisfactory,  and  as  affording 
the  first  step  toward  a  more  complete  and  explanatory  theory. 
It  seems  now  a  most  amazing  thing  that  even  to  argue  for  this 
first  step  was  accounted  a  heresy,  and  was  almost  universally 
condemned  as  being  opposed  to  the  teaching  of  both  science 
and  religion ! 

The  book  was,  however,  as  great  a  success  as,  later  on,  was 
Darwin's  "  Origin  of  Species."  Four  editions  were  issued  in 
the  first  seven  months,  and  by  1 860  it  had  reached  the  eleventh 
edition,  and  about  24,000  copies  had  been  sold.  It  is  certain 
that  this  work  did  great  service  in  familiarizing  the  reading- 
public  with  the  idea  of  evolution,  and  thus  preparing  them  for 
the  more  complete  and  efficient  theory  laid  before  them  by 
Darwin. 

During  the  fifteen  years  succeeding  the  publication  of  the 
"  Vestiges  "  many  naturalists  expressed  their  belief  in  the  pro- 
gressive development  of  organic  forms;  while  in  1852  Herbert 
Spencer  published  his  essay  contrasting  the  theories  of  Crea- 
tion and  Development  with  such  skill  and  logical  power  as  to 
carry  conviction  to  the  minds  of  all  unprejudiced  readers ;  but 
none  of  these  writers  suggested  any  definite  theory  of  how  the 
change  of  species  actually  occurred.  That  was  first  done  in 


342  ACHIEVEMENTS  IN  SCIENCE 

1858;  and  in  connection  with  it  I  may,  perhaps,  venture  to  give 
a  few  personal  details. 

Ever  since  I  read  the  "  Vestiges "  I  had  been  convinced 
that  development  took  place  by  means  of  the  ordinary  process 
of  reproduction ;  but  though  this  was  widely  admitted,  no  one 
had  set  forth  the  various  kinds  of  evidence  that  rendered  it 
almost  a  certainty.  I  endeavored  to  do  this  in  an  article  written 
at  Sarawak  in  February,  1855,  which  was  published  in  the  fol- 
lowing September  in  the  "Annals  of  Natural  History."  Rely- 
ing mainly  on  the  well-known  facts  of  geographical  distribution 
and  geological  succession,  I  deduced  from  them  the  law,  or 
generalization,  that  "Every  species  has  come  into  existence 
coincident  both  in  Space  and  Time  with  a  Pre-existing  closely 
allied  Species " ;  and  I  showed  how  many  peculiarities  in  the 
affinities,  the  succession,  and  the  distribution  of  the  forms  of 
life  were  explained  by  this  hypothesis,  and  that  no  important 
facts  contradicted  it. 

Even  then,  however,  I  had  no  conception  of  how  or  why 
each  new  form  had  come  into  existence  with  all  its  beautiful 
adaptations  to  its  special  mode  of  life;  and  though  the  subject 
was  continually  being  pondered  over,  no  light  came  to  me  till 
three  years  later  (February,  1858),  under  somewhat  peculiar 
circumstances.  I  was  then  living  at  Ternate  in  the  Moluccas, 
and  was  suffering  from  a  rather  severe  attack  of  intermittent 
fever,  which  prostrated  me  for  several  hours  every  day  during 
the  cold  and  succeeding  hot  fits.  During  one  of  these  fits,  while 
again  considering  the  problem  of  the  origin  of  species,  some- 
thing led  me  to  think  of  Mai  thus' s  Essay  on  Population  (which 
I  had  read  about  ten  years  before),  and  the  "  positive  checks  " 
— war,  disease,  famine,  accidents,  etc. — which  he  adduced  as 
keeping  all  savage  populations  nearly  stationary.  It  then 
occurred  to  me  that  these  checks  must  also  act  upon  animals, 
and  keep  down  their  numbers ;  and  as  they  increase  so  much 
faster  than  man  does,  while  their  numbers  are  always  very 
nearly  or  quite  stationary,  it  was  clear  that  these  checks  in 
their  case  must  be  far  more  powerful,  since  a  number  equal  to 
the  whole  increase  must  be  cut  off  by  them  every  year.  While 
vaguely  thinking  how  this  would  affect  any  species,  there  sud- 


EVOLUTION  AND  NATURE  STUDIES          343 

denly  flashed  upon  me  the  idea  of  the  survival  of  the  fittest — 
that  the  individuals  removed  by  these  checks  must  be,  on  the 
whole,  inferior  to  those  that  survived.  Then,  considering  the 
variations  continually  occurring  in  every  fresh  generation  of 
animals  or  plants,  and  the  changes  of  climate,  of  food,  of  ene- 
mies always  in  progress,  the  whole  method  of  specific  modifica- 
tion became  clear  to  me,  and  in  the  two  hours  of  my  fit  I  had 
thought  out  the  main  points  of  the  theory.  That  same  evening 
I  sketched  out  the  draft  of  a  paper;  in  the  two  succeeding 
evenings  I  wrote  it  out,  and  sent  it  by  the  next  post  to  Mr. 
Darwin.  I  fully  expected  it  would  be  as  new  to  him  as  it  was 
to  myself,  because  he  had  informed  me  by  letter  that  he  was 
engaged  on  a  work  intended  to  show  in  what  way  species  and 
varieties  differ  from  each  other,  adding,  "  my  work  will  not  fix 
or  settle  anything."  I  was  therefore  surprised  to  find  that  he 
had  really  arrived  at  the  very  same  theory  as  mine  long  before 
(in  1844),  had  worked  it  out  in  considerable  detail,  and  had 
shown  the  MSS.  to  Sir  Charles  Lyell  and  Sir  Joseph  Hooker; 
and  on  their  recommendation  my  paper  and  sufficient  extracts 
from  his  MSS.  work  were  read  at  a  meeting  of  the  Linnean 
Society  in  July  of  the  same  year,  when  the  theory  of  Natural 
Selection,  or  survival  of  the  fittest,  was  first  made  known  to 
the  world.  But  it  received  little  attention  till  Darwin's  great 
and  epoch-making  book  appeared  at  the  end  of  the  following 
year. 

We  may  best  attain  to  some  estimate  of  the  greatness  and 
completeness  of  Darwin's  work  by  considering  the  vast  change 
in  educated  public  opinion  which  it  rapidly  and  permanently 
effected.  What  that  opinion  was  before  it  appeared  is  shown 
by  the  fact  that  neither  Lamarck,  nor  Herbert  Spencer,  nor  the 
author  of  the  "Vestiges,"  had  been  able  to  make  any  impres- 
sion upon  it.  The  very  idea  of  progressive  development  of 
species  from  other  species  was  held  to  be  a  "  heresy  "  by  such 
great  and  liberal-minded  men  as  Sir  John  Herschel  and  Sir 
Charles  Lyell ;  the  latter  writer  declaring,  in  the  earlier  editions 
of  his  great  work,  that  the  facts  of  geology  were  "  fatal  to  the 
theory  of  progressive  development."  The  whole  literary  and 
scientific  worlds  were  violently  opposed  to  all  such  theories,  and 


344  ACHIEVEMENTS  IN  SCIENCE 

altogether  disbelieved  in  the  possibility  of  establishing  them. 
It  had  been  so  long  the  custom  to  treat  species  as  special  crea- 
tions, and  the  mode  of  their  creation  as  "  the  mystery  of  mys- 
teries," that  it  had  come  to  be  considered  not  only  presumptu- 
ous, but  almost  impious,  for  any  individual  to  profess  to  have 
lifted  the  veil  from  what  was  held  to  be  the  greatest  and  most 
mysterious  of  Nature's  secrets. 

But  what  is  the  state  of  educated  literary  and  scientific 
opinion  at  the  present  day?  Evolution  is  now  universally 
accepted  as  a  demonstrated  principle,  and  not  one  single  writer 
of  the  slightest  eminence,  that  I  am  aware  of,  declares  his  dis- 
belief in  it.  This  is,  of  course,  partly  due  to  the  colossal  work 
of  Herbert  Spencer ;  but  for  one  reader  of  his  works  there  are 
probably  ten  of  Darwin's,  and  the  establishment  of  the  theory 
of  the  "  origin  of  Species  by  Means  of  Natural  Selection  "  is 
wholly  Darwin's  work.  That  book,  together  with  those  which 
succeeded  it,  has  so  firmly  established  the  doctrine  of  progres- 
sive development  of  species  by  the  ordinary  processes  of  multi- 
plication and  variation  that  there  is  now,  I  believe,  scarcely  a 
single  living  naturalist  who  doubts  it.  What  was  a  "great 
heresy  "  to  Sir  John  Herschel  in  1845,  and  "  the  mystery  of  mys- 
teries "  down  to  the  date  of  Darwin's  book,  is  now  the  common 
knowledge  of  every  clever  schoolboy,  and  of  every  one  who 
reads  even  the  newspapers.  The  only  thing  discussed  now  is, 
not  the  fact  of  evolution — that  is  admitted — but  merely  whether 
or  no  the  causes  alleged  by  Darwin  are  themselves  sufficient  to 
explain  evolution  of  species,  or  require  to  be  supplemented  by 
other  causes,  known  or  unknown.  Probably  so  complete  a 
change  of  educated  opinion,  on  a  question  of  such  vast  difficulty 
and  complexity,  was  never  before  effected  in  so  short  a  time. 
It  not  only  places  the  name  of  Darwin  on  a  level  with  that  of 
Newton,  but  his  work  will  always  be  considered  as  one  of  the 
greatest,  if  not  the  very  greatest,  of  the  scientific  achievements 
of  the  nineteenth  century,  rich  as  that  century  has  been  in 
great  discoveries  in  every  department  of  physical  science. 


EVOLUTION  AND  NATURE  STUDIES 


Bees  in  the  Hive 

By  ARABELLA  B.   BUCKLEY 

I  AM  going  to  ask  you  to  visit  with  me  to-day  one  of  the  most 
wonderful  cities  in  the  world.  It  is  a  city  with  no  human 
beings  in  it,  and  yet  it  is  densely  populated,  for  such  a  city  may 
contain  from  20,000  to  60,000  inhabitants.  In  it  you  will  find 
streets,  but  no  pavements,  for  the  inhabitants  walk  along  the 
walls  of  the  houses ;  while  in  the  houses  you  will  see  no  win- 
dows, for  each  house  just  fits  its  owner,  and  the  door  is  the 
only  opening  in  it.  Though  made  without  hands,  these  houses 
are  most  evenly  and  regularly  built  in  tiers  one  above  the  other; 
and  here  and  there  a  few  royal  palaces,  larger  and  more  spa- 
cious than  the  rest,  catch  the  eye  conspicuously  as  they  stand 
out  at  the  corners  of  the  streets. 

Some  of  the  ordinary  houses  are  used  to  live  in,  while 
others  serve  as  storehouses  where  food  is  laid  up  in  the  sum- 
mer to  feed  the  inhabitants  during  the  winter,  when  they  are 
not  allowed  to  go  outside  the  walls.  Not  that  the  gates  are 
ever  shut ;  that  is  not  necessary,  for  in  this  wonderful  city  each 
citizen  follows  the  laws ;  going  out  when  it  is  time  to  go  out, 
coming  home  at  proper  hours,  and  staying  at  home  when  it  is 
his  or  her  duty.  And  in  the  winter,  when  it  is  very  cold  out- 
side, the  inhabitants,  having  no  fires,  keep  themselves  warm 
within  the  city  by  clustering  together,  and  never  venturing  out 
of  doors. 

One  single  queen  reigns  over  the  whole  of  this  numerous 
population,  and  you  might  perhaps  fancy  that,  having  so  many 
subjects  to  work  for  her  and  wait  upon  her,  she  would  do  noth- 

345 


346  ACHIEVEMENTS  IN  SCIENCE 

ing  but  amuse  herself.  On  the  contrary,  she,  too,  obeys  the 
laws  laid  down  for  her  guidance,  and  never,  except  on  one  or 
two  state  occasions,  goes  out  of  the  city,  but  works  as  hard  as 
the  rest  in  performing  her  own  royal  duties. 

From  sunrise  to  sunset,  whenever  the  weather  is  fine,  all  is 
life,  activity,  and  bustle  in  this  busy  city.  Though  the  gates 
are  so  narrow  that  two  inhabitants  can  only  just  pass  each  other 
on  their  way  through  them,  yet  thousands  go  in  and  out  every 
hour  of  the  day;  some  bringing  in  materials  to  build  new 
houses,  others  food  and  provisions  to  store  up  for  the  winter ; 
and  while  all  appears  confusion  and  disorder  among  this  rapidly 
moving  throng,  yet  in  reality  each  has  her  own  work  to  do,  and 
perfect  order  reigns  over  the  whole. 

Even  if  you  did  not  already  know  from  the  title  of  the  lec- 
ture what  city  this  is  that  I  am  describing,  you  would  no  doubt 
guess  that  it  is  a  bee-hive.  For  where  in  the  whole  world,  ex- 
cept indeed  upon  an  ant-hill,  can  we  find  so  busy,  so  industrious, 
or  so  orderly  a  community  as  among  the  bees  ?  More  than  a 
hundred  years  ago,  a  blind  naturalist,  Francois  Huber,  set  him- 
self to  study  the  habits  of  these  wonderful  insects,  and  with  the 
help  of  his  wife  and  an  intelligent  man-servant,  managed  to 
learn  most  of  their  secrets.  Before  his  time  all  naturalists  had 
failed  in  watching  bees,  because  if  they  put  them  in  hives  with 
glass  windows,  the  bees,  not  liking  the  light,  closed  up  the  win- 
dows with  cement  before  they  began  to  work.  But  Huber  in- 
vented a  hive  which  he  could  open  and  close  at  will,  putting  a 
glass  hive  inside  it,  and  by  this  means  he  was  able  to  surprise 
the  bees  at  their  work.  Thanks  to  his  studies,  and  to  those  of 
other  naturalists  who  have  followed  in  his  steps,  we  now  know 
almost  as  much  about  the  home  of  bees  as  we  do  about  our 
own ;  and  if  we  follow  out  to-day  the  building  of  a  bee-city  and 
the  life  of  its  inhabitants,  I  think  you  will  acknowledge  that 
they  are  a  wonderful  community,  and  that  it  is  a  great  compli- 
ment to  any  one  to  say  that  he  or  she  is  "  as  busy  as  a  bee." 

In  order  to  begin  at  the  beginning  of  the  story,  let  us  sup- 
pose that  we  go  into  a  country  garden  one  fine  morning  in  May 
when  the  sun  is  shining  brightly  overhead,  and  that  we  see 
hanging  from  the  bough  of  an  old  apple-tree  a  black  object 


EVOLUTION  AND  NATURE  STUDIES         347 

which  looks  very  much  like  a  large  plum-pudding.  On  ap- 
proaching it,  however,  we  see  that  it  is  a  large  cluster  or  swarm 
of  bees  clinging  to  each  other  by  their  legs ;  each  bee  with  its 
two  fore-legs  clinging  to  the  two  hinder-legs  of  the  one  above 
it.  In  this  way  as  many  as  20,000  bees  may  be  clinging  to- 
gether, and  yet  they  hang  so  freely  that  a  bee,  even  from  quite 
the  center  of  the  swarm,  can  disengage  herself  from  her  neigh- 
bors and  pass  through  to  the  outside  of  the  cluster  whenever 
she  wishes. 

If  these  bees  were  left  to  themselves,  they  would  find  a 
home  after  a  time  in  a  hollow  tree,  or  under  the  roof  of  a  house, 
or  in  some  other  cavity,  and  begin  to  build  their  honeycomb 
there.  But  as  we  do  not  wish  to  lose  their  honey  we  will  bring 
a  hive,  and,  holding  it  under  the  swarm,  shake  the  bough  gently 
so  that  the  bees  fall  into  it,  and  cling  to  the  sides  as  we  turn  it 
over  on  a  piece  of  clean  linen,  on  the  stand  where  the  hive  is 
to  be. 

And  now  let  us  suppose  that  we  are  able  to  watch  what  is 
going  on  in  the  hive.  Before  five  minutes  are  over  the  indus- 
trious little  insects  have  begun  to  disperse  and  to  make  arrange- 
ments in  their  new  home.  A  number  (perhaps  about  two  thou- 
sand) of  large,  lumbering  bees,  of  a  darker  color  than  the  rest, 
will,  it  is  true,  wander  aimlessly  about  the  hive,  and  wait  for 
the  others  to  feed  them  and  house  them ;  but  these  are  the 
drones,  or  male  bees,  who  never  do  any  work  except  during  one 
or  two  days  in  their  whole  lives.  But  the  smaller  working  bees 
begin  to  be  busy  at  once.  Some  fly  off  in  search  of  honey. 
Others  walk  carefully  all  around  the  inside  of  the  hive  to  see 
whether  there  are  any  cracks  in  it ;  and  if  there  are,  they  go 
off  to  the  horse-chestnut  trees,  poplars,  hollyhocks,  or  other 
plants  which  have  sticky  buds,  and  gather  a  kind  of  gum  called 
"  propolis,"  with  which  they  cement  the  cracks  and  make  them 
air-tight.  Others  again,  cluster  round  one  bee,  blacker  than 
the  rest  and  having  a  longer  body  and  shorter  wings ;  for  this 
is  the  queen  bee,  the  mother  of  the  hive,  and  she  must  be 
watched  and  tended. 

But  the  largest  number  begin  to  hang  in  a  cluster  from  the 
roof  just  as  they  did  from  the  bough  of  the  apple-tree.  What 


348  ACHIEVEMENTS  IN  SCIENCE 

are  they  doing  there  ?  Watch  for  a  little  while  an  you  will 
soon  see  one  bee  come  out  from  among  its  companions  and  set- 
tle on  the  top  of  the  inside  of  the  hive,  turning  herself  round 
and  round,  so  as  to  push  the  other  bees  back  and  to  make  a 
space  in  which  she  can  work.  Then  she  will  begin  to  pick  at 
the  under  part  of  her  body  with  her  fore-legs,  and  will  bring  a 
scale  of  wax  from  a  curious  sort  of  pocket  under  her  abdomen. 
Holding  this  wax  in  her  claws,  she  will  bite  it  with  her  hard, 
pointed  upper  jaws,  which  move  to  and  fro  sideways  like  a  pair 
of  pincers ;  then,  moistening  it  with  her  tongue  into  a  kind  of 
paste,  she  will  draw  it  out  like  a  ribbon  and  plaster  it  on  the 
top  of  the  hive. 

After  that  she  will  take  another  piece ;  for  she  has  eight  of 
these  little  wax-pockets,  and  she  will  go  on  till  they  are  all  ex- 
hausted. Then  she  will  fly  away  out  of  the  hive,  leaving  a 
small  wax  lump  on  the  hive  ceiling  or  on  the  bar  stretched 
across  it ;  then  her  place  will  be  taken  by  another  bee,  who  will 
go  through  the  same  maneuvers.  This  bee  will  be  followed 
by  another,  and  another,  till  a  large  wall  of  wax  has  been  built, 
hanging  from  the  bar  of  the  hive. 

Meanwhile,  the  bees  which  have  been  gathering  honey  out 
of  doors  begin  to  come  back  laden.  But  they  cannot  store 
their  honey,  for  there  are  no  cells  made  yet  to  put  it  in ;  neither 
can  they  build  combs  with  the  rest,  for  they  have  no  wax  in 
their  wax-pockets.  So  they  just  go  and  hang  quietly  on  to  the 
other  bees,  and  there  they  remain  for  twenty-four  hours,  during 
which  time  they  digest  the  honey  they  have  gathered,  and  part 
of  it  forms  wax  and  oozes  out  from  the  scales  under  their  body. 
Then  they  are  prepared  to  join  the  others  at  work  and  plaster 
wax  on  to  the  hive. 

And  now,  as  soon  as  a  rough  lump  of  wax  is  ready,  another 
set  of  bees  come  to  do  its  work.  These  are  called  the  nursing 
bees,  because  they  prepare  the  cells  and  feed  the  young  ones. 
One  of  these  bees,  standing  on  the  roof  of  the  hive,  begins  to 
force  her  head  into  the  wax,  biting  with  her  jaws  and  moving 
her  head  to  and  fro.  Soon  she  has  made  the  beginning  of  a 
round  hollow,  and  then  she  passes  on  to  make  another,  while  a 
second  bee  takes  her  place  and  enlarges  the  first  one.  As 


EVOLUTION  AND  NATURE  STUDIES         349 

many  as  twenty  bees  will  be  employed  in  this  way,  one  after 
another,  upon  each  hole  before  it  is  large  enough  for  the  base 
of  a  cell. 

Meanwhile  another  set  of  nursing  bees  has  been  working 
just  in  the  same  way  on  the  other  side  of  the  wax,  and  so  a 
series  of  hollows  are  made  back  to  back  all  over  the  comb. 
Then  the  bees  form  the  walls  of  the  cells,  and  soon  a  number 
of  six-sided  tubes,  about  half  an  inch  deep,  stand  all  along  each 
side  of  the  comb  ready  to  receive  honey  or  bee-eggs. 

These  cells  fit  closely  into  each  other;  even  the  ends  are  so 
shaped  that,  as  they  lie  back  to  back,  the  bottom  of  one  cell  fits 
into  the  space  between  the  ends  of  three  cells  meeting  it  from 
the  opposite  side,  while  they  fit  into  the  spaces  round  it.  Upon 
this  plan  the  clever  little  bees  fill  every  atom  of  space,  use  the 
least  possible  quantity  of  wax,  and  make  the  cells  lie  so  closely 
together  that  the  whole  comb  is  kept  warm  when  the  young 
bees  are  in  it. 

There  are  some  kinds  of  bees  who  do  not  live  in  hives,  but 
each  one  builds  a  home  of  its  own.  These  bees — such  as  the 
upholsterer  bee,  which  digs  a  hole  in  the  earth  and  lines  it  with 
flowers  and  leaves,  and  the  mason  bee,  which  builds  in  walls- 
do  not  make  six-sided  cells,  but  round  ones,  for  room  is  no 
object  to  them.  But  nature  has  gradually  taught  the  little 
hive-bee  to  build  its  cells  more  and  more  closely,  till  they  fit 
perfectly  within  each  other.  If  you  make  a  number  of  round 
holes  close  together  in  a  soft  substance,  and  then  squeeze  the 
substance  evenly  from  all  sides,  the  holes  will  gradually  take  a 
six-sided  form,  showing  that  this  is  the  closest  shape  into  which 
they  can  be  compressed.  Although  the  bee  does  not  know 
this,  yet  as  she  gnaws  away  every  bit  of  wax  that  can  be  spared, 
she  brings  the  holes  into  this  shape. 

As  soon  as  one  comb  is  finished,  the  bees  begin  another  by 
the  side  of  it,  leaving  a  narrow  lane  between,  just  broad  enough 
for  two  bees  to  pass  back  to  back  as  they  crawl  along,  and  so 
the  work  goes  on  till  the  hive  is  full  of  combs. 

As  soon,  however,  as  a  length  of  about  five  or  six  inches  of 
the  first  comb  has  been  made  into  cells,  the  bees  which  are 
bringing  home  honey  no  longer  hang  to  make  it  into  wax,  but 


350  ACHIEVEMENTS  IN  SCIENCE 

begin  to  store  it  in  the  cells.  When  the  bee  goes  to  fetch  her 
honey  she  settles  on  a  flower,  thrusts  into  it  her  small  tongue- 
like  proboscis,  which  is  really  a  lengthened  under-lip,  and  sucks 
out  the  drop  of  honey.  This  she  swallows,  passing  it  down  her 
throat  into  a  honey-bag  or  first  stomach,  which  lies  between  her 
throat  and  her  real  stomach,  and  when  she  gets  back  to  the 
hive  she  can  empty  this  bag  and  pass  the  honey  back  through 
her  mouth  again  into  the  honey-cells. 

But  if  you  watch  bees  carefully,  especially  in  the  spring 
time,  you  will  find  that  they  carry  off  something  else  besides 
honey.  Early  in  the  morning,  when  the  dew  is  on  the  ground, 
or  later  in  the  day,  in  moist,  shady  places,  you  may  see  a  bee 
rubbing  itself  against  a  flower,  or  biting  bags  of  yellow  dust,  or 
pollen.  When  she  has  covered  herself  with  this  she  will  brush 
it  off  with  her  feet,  and,  bringing  it  to  her  mouth,  she  will 
moisten  and  roll  it  into  a  little  ball,  and  then  pass  it  back  from 
the  first  pair  of  legs  to  the  second,  and  so  to  the  third  or  hinder 
pair.  Here  she  will  pack  it  into  a  little  hairy  groove,  called  a 
"basket,"  in  the  joint  of  one  of  the  hind  legs,  where  you  may 
see  it,  looking  like  a  swelled  joint,  as  she  hovers  among  the 
flowers.  She  often  fills  both  hind  legs  in  this  way,  and  when 
she  arrives  at  the  hive  the  nursing  bees  take  the  lumps  from 
her,  and  eat  it  themselves,  or  mix  it  with  honey  to  feed  the 
young  bees ;  or,  when  they  have  any  to  spare,  store  it  away  in 
old  honey-cells  to  be  used  by  and  by.  This  is  the  dark,  bit- 
ter stuff  called  "  bee-bread,"  which  you  often  find  in  a  honey- 
comb, especially  in  a  comb  which  has  been  filled  late  in  the 
summer. 

When  the  bee  has  been  relieved  of  the  bee-bread  she  goes 
off  to  one  of  the  clean  cells  in  the  new  comb  and,  standing  on 
the  edge,  throws  up  honey  from  the  honey-bag  into  the  cell. 
One  cell  will  hold  the  contents  of  many  honey-bags,  and  so  the 
bnsy  little  workers  have  to  work  all  day  filling  cell  after  cell,  in 
which  the  honey  lies  uncovered,  being  too  thick  and  sticky  to 
flow  out,  and  is  used  for  daily  food — unless  there  is  any  to 
spare,  and  then  they  close  up  the  cells  with  wax  to  keep  for 
the  winter. 

Meanwhile,  a  day  or  two  after  the  bees  have  settled  in  the 


EVOLUTION  AND  NATURE  STUDIES          351 

hive,  the  queen  bee  begins  to  get  very  restless.  She  goes  out- 
side  the  hive  and  hovers  about  a  little  while,  and  then  comes  in 
again,  and  though  generally  the  bees  all  look  very  closely  after 
her  to  keep  her  indoors,  yet  now  they  let  her  do  as  she  likes. 
Again  she  goes  out,  and  again  back,  and  then,  at  last,  she  soars 
up  into  the  air  and  flies  away.  But  she  is  not  allowed  to  go 
alone.  All  the  drones  of  the  hive  rise  up  after  her,  forming  a 
guard  of  honor  to  follow  her  wherever  she  goes. 

In  about  half  an  hour  she  comes  back  again,  and  then  the 
working  bees  all  gather  round  her,  knowing  that  now  she  will 
remain  quietly  in  the  hive  and  spend  all  her  time  in  laying 
eggs ;  for  it  is  the  queen  bee  who  lays  all  the  eggs  in  the  hive. 
This  she  begins  to  do  about  two  days  after  her  flight.  There 
are  now  many  cells  ready  besides  those  filled  with  honey ;  and, 
escorted  by  several  bees,  the  queen  bee  goes  to  one  of  these, 
and  putting  her  head  into  it,  remains  there  a  second,  as  if  she 
were  examining  whether  it  would  make  a  good  home  for  the 
young  bee.  Then,  coming  out,  she  turns  round  and  lays  a 
small,  oval,  bluish-white  egg  in  the  cell.  After  this  she  takes 
no  more  notice  of  it,  but  goes  on  to  the  next  cell  and  the  next, 
doing  the  same  thing,  and  laying  eggs  in  all  the  empty  cells 
equally  on  both  sides  of  the  comb.  She  goes  on  so  quickly 
that  she  sometimes  lays  as  many  as  two  hundred  eggs  in  one 
day. 

Then  the  work  of  the  nursing  bees  begins.  In  two  or  three 
ys  each  egg  has  become  a  tiny  maggot  or  larva,  and  the  nurs- 
g  bees  put  into  its  cell  a  mixture  of  pollen  and  honey  which 
ey  have  prepared  in  their  own  mouths,  thus  making  a  kind  of 
weet  bath  in  which  the  larva  lies.  In  five  or  six  days  the  larva 
grows  so  fat  upon  this  that  it  nearly  fills  the  cell,  and  then  the 
bees  seal  up  the  mouth  of  the  cell  with  a  thin  cover  of  wax* 
made  of  little  rings,  and  with  a  tiny  hole  in  the  center. 

As  soon  as  the  larva  is  covered  in,  it  begins  to  give  out 
from  its  under-lip  a  whitish,  silken  film  made  of  two  threads  of 
silk  glued  together,  and  with  this  it  spins  a  covering  or  cocoon 
all  round  itself,  and  so  it  remains  for  about  ten  days  more.  At 
last,  just  twenty-one  days  after  the  egg  was  laid,  the  young  bee 
is  quite  perfect,  and  begins  to  eat  her  way  through  the  cocoon 


352  ACHIEVEMENTS  IN  SCIENCE 

and  through  the  waxen  lid,  and  scrambles  out  of  her  cell.  Then 
the  nurses  come  again  to  her,  stroke  her  wings  and  feed  her  for 
twenty-four  hours,  and  after  that  she  is  quite  ready  to  begin 
work,  and  flies  out  to  gather  honey  and  pollen  like  the  rest  of 
the  workers. 

By  this  time  the  number  of  working  bees  in  the  hive  is  be- 
coming very  great,  and  the  storing  of  honey  and  pollen-dust 
goes  on  very  quickly.  Even  the  empty  cells  which  the  young 
bees  have  left  are  cleaned  out  by  the  nurses  and  filled  with 
honey ;  and  this  honey  is  darker  than  that  stored  in  clean  cells, 
and  which  we  always  call  "  virgin  honey,"  because  it  is  so  pure 
and  clear. 

At  last,  after  six  weeks,  the  queen  leaves  off  laying  worker- 
eggs  and  begins  to  lay,  in  some  rather  larger  cells,  eggs  from 
which  drones,  or  male  bees,  will  grow  up  in  about  twenty  days. 
Meanwhile,  the  worker-bees  have  been  building  on  the  edge  of 
the  cones  some  very  curious  cells  which  look  like  thimbles 
hanging  with  the  open  side  upward,  and  about  every  three 
days  the  queen  stops  laying  drone-eggs  and  goes  to  put  an  egg 
in  one  of  these  cells.  Notice  that  she  waits  three  days  between 
each  of  these  peculiar  layings,  because  we  shall  see  presently 
that  there  is  a  good  reason  for  her  doing  so. 

The  nursing  bees  take  great  care  of  these  eggs,  and  instead 
of  putting  ordinary  food  into  the  cell,  they  fill  it  with  a  sweet, 
pungent  jelly,  for  this  larva  is  to  become  a  princess  and  a  future 
queen  bee.  Curiously  enough,  it  seems  to  be  the  peculiar  food 
and  the  size  of  the  cell  which  makes  the  larva  grow  into  a 
mother-bee  which  can  lay  eggs,  for  if  a  hive  has  the  misfortune 
to  lose  its  queen,  they  take  one  of  the  ordinary  worker-larvae 
and  put  it  into  a  royal  cell,  and  feed  it  with  jelly,  and  it  be- 
comes a  queen-bee.  As  soon  as  the  princess  is  shut  in  like  the 
others,  she  begins  to  spin  her  cocoon,  but  she  does  not  quite 
close  it  as  the  other  bees  do,  but  leaves  a  hole  at  the  top. 

At  the  end  of  sixteen  days  after  the  first  royal  egg  is  laid, 
the  eldest  princess  begins  to  try  to  eat  her  way  out  of  her  cell, 
and  about  this  time  the  old  queen  becomes  very  uneasy,  and 
wanders  about  distractedly.  The  reason  of  this  is  that  there 
can  never  be  two  queen  bees  in  one  hive,  and  the  queen  knows 


EVOLUTION  AND  NATURE  STUDIES          353 

that  her  daughter  will  soon  be  coming  out  of  her  cradle  and 
will  try  to  turn  her  off  her  throne..  So,  not  wishing  to  have 
to  fight  for  her  kingdom,  she  makes  up  her  mind  to  seek  a  new 
home  and  take  a  number  of  her  subjects  with  her.  If  you  watch 
the  hive  about  this  time,  you  will  notice  many  of  the  bees  clus- 
tering together  after  they  have  brought  in  their  honey,  and 
hanging  patiently,  in  order  to  have  plenty  of  wax  ready  to  use 
when  they  start,  while  the  queen  keeps  a  sharp  lookout  for  a 
bright,  sunny  day  on  which  they  can  swarm ;  for  bees  will  never 
swarm  on  a  wet  or  doubtful  day  if  they  can  possibly  help  it,  and 
we  can  easily  understand  why,  when  we  consider  how  the  rain 
would  clog  their  wings  and  spoil  the  wax  under  their  bodies. 

Meanwhile  the  young  princess  grows  very  impatient,  and 
tries  to  get  out  of  her  cell,  but  the  worker-bees  drive  her  back, 
for  they  know  there  would  be  a  terrible  fight  if  the  two  queens 
met.  So  they  close  up  the  hole  she  has  made  with  fresh  wax, 
after  having  put  in  some  food  for  her  to  live  upon  till  she  is 
released. 

At  last  a  suitable  day  arrives,  and  about  ten  or  eleven  o'clock 
in  the  morning  the  old  queen  leaves  the  hive,  taking  with  her 
about  2,000  drones  and  from  12,000  to  20,000  worker-bees, 
which  fly  a  little  way,  clustering  round  her  till  she  alights  on 
the  bough  of  some  tree,  and  then  they  form  a  compact  swarm 
ready  for  a  new  hive  or  to  find  a  home  of  their  own. 

Leaving  them  to  go  their  way,  we  will  now  return  to  the 
old  hive.  Here  the  liberated  princess  is  reigning  in  all  her 
glory;  the  worker-bees  crowd  round  her,  watch  over  her,  and 
feed  her,  as  though  they  could  not  do  enough  to  show  her 
honor.  But  still  she  is  not  happy.  She  is  restless,  and  runs 
about  as  if  looking  for  an  enemy,  and  she  tries  to  get  at  the 
remaining  royal  cells  where  the  other  young  princesses  are  still 
shut  in.  But  the'  workers  will  not  let  her  touch  them,  and  at 
last  she  stands  still  and  begins  to  beat  the  air  with  her  wings 
and  to  tremble  all  over,  moving  more  and  more  quickly,  till  she 
makes  quite  a  loud,  piping  noise. 

Hark!  What  is  that  note  answering  her?  It  is  a  low, 
hoarse  sound,  and  it  comes  from  the  cell  of  the  next  eldest 
princess.  Now  we  see  why  the  young  queen  has  been  so  rest- 
23 


354  ACHIEVEMENTS  IN  SCIENCE 

less.  She  knows  her  sister  will  soon  come  out,  and  the  louder 
and  stronger  the  sound  becomes  within  the  cell,  the  sooner  she 
knows  the  fight  will  have  to  begin.  And  so  she  makes  up  her 
mind  to  follow  her  mother's  example  and  to  lead  off  a  second 
swarm.  But  she  cannot  always  stop  to  choose  a  fine  day,  for 
her  sister  is  growing  very  strong  and  may  come  out  of  her  cell 
before  she  is  off.  And  so  the  second,  or  after  swarm,  gets 
ready  and  goes  away.  And  this  explains  why  princesses'  eggs 
are  laid  a  few  days  apart,  for  if  they  were  laid  all  on  the  same 
day,  there  would  be  no  time  for  one  princess  to  go  off  with  a 
swarm  before  the  other  came  out  of  her  cell.  Sometimes, 
when  the  workers  are  not  watchful  enough,  two  queens  do 
meet,  and  then  they  fight  till  one  is  killed ;  or  sometimes  they 
both  go  off  with  the  same  swarm  without  finding  each  other 
out.  But  this  only  delays  the  fight  till  they  get  into  the  new 
hive ;  sooner  or  later  one  must  be  killed. 

And  now  a  third  queen  begins  to  reign  in  the  old  hive,  and 
she  is  just  as  restless  as  the  preceding  ones,  for  there  are  still 
more  princesses  to  be  born.  But  this  time,  if  no  new  swarm 
wants  to  start,  the  workers  do  not  try  to  protect  the  royal  cells. 
The  young  queen  darts  at  the  first  she  sees,  gnaws  a  hole  with 
her  jaws,  and,  thrusting  in  her  sting  through  the  hole  in  the 
cocoon,  kills  the  young  bee  while  it  is  still  a  prisoner.  She 
then  goes  to  the  next,  and  the  next,  and  never  rests  till  all  the 
young  princesses  are  destroyed.  Then  she  is  contented,  for 
she  knows  no  other  queen  will  come  to  dethrone  her.  After  a 
few  days  she  takes  her  flight  in  the  air  with  the  drones,  and 
comes  home  to  settle  down  in  the  hive  for  the  winter. 

Then  a  very  curious  scene  takes  place.  The  drones  are  no 
more  use,  for  the  queen  will  not  fly  out  again,  and  these  idle 
bees  will  never  do  any  work  in  the  hive.  So  the  worker-bees 
begin  to  kill  them,  falling  upon  them  and  stinging  them  to 
death,  and,  as  the  drones  have  no  stings,  they  cannot  defend 
themselves,  and  in  a  few  days  there  is  not  a  drone,  nor  even  a 
drone-egg,  left  in  the  hive.  This  massacre  seems  very  sad  to 
us,  since  the  poor  drones  have  never  done  any  harm  beyond 
being  hopelessly  idle.  But  it  is  less  sad  when  we  know  that 
they  could  not  live  many  weeks,  even  if  they  were  not  attacked, 


EVOLUTION  AND  NATURE  STUDIES 


355 


and,  with  winter  coming,  the  bees  could  not  afford  to  feed  use- 
less mouths,  so  a  quick  death  is  probably  happier  for  them  than 
starvation. 

And  now  all  the  remaining  inhabitants  of  the  hive  settle 
down  to  feeding  the  young  bees  and  laying  in  the  winter's  store. 
It  is  at  this  time,  after  they  have  been  toiling  and  saving,  that 
we  come  and  take  their  honey ;  and  from  a  well-stocked  hive 
we  may  even  take  thirty  pounds,  without  starving  the  industri- 
ous little  inhabitants.  But  then  we  must  often  feed  them  in 
return,  and  give  them  sweet  syrup  in  the  late  autumn  and  the 
next  early  spring  when  they  cannot  find  any  flowers. 

Although  the  hive  has  now  become  comparatively  quiet  and 
the  work  goes  on  without  excitement,  yet  every  single  bee  is 
employed  in  some  way  either  out  of  doors  or  about  the  hive. 
Besides  the  honey  collectors  and  the  nurses,  a  certain  number 
of  bees  are  told  off  to  ventilate  the  hive,  for  naturally  where  so 
many  insects  are  packed  closely  together  the  heat  will  become 
very  great,  and  the  air  impure  and  unwholesome.  And  the 
bees  have  no  windows  that  they  can  open  to  let  in  fresh  air,  so 
they  are  obliged  to  fan  it  in  from  the  one  opening  of  the  hive. 
The  way  in  which  they  do  this  is  very  interesting.  Some  of 
the  bees  stand  close  to  the  entrance,  with  their  faces  toward 
it,  and  opening  their  wings,  so  as  to  make  them  into  fans,  they 
wave  them  to  and  fro,  producing  a  current  of  air.  Behind 
these  bees,  and  all  over  the  floor  of  the  hive,  there  stand  others, 
this  time  with  their  backs  toward  the  entrance,  and  fan  in  the 
same  manner,  and  in  this  way  air  is  sent  into  all  the  passages. 

Another  set  of  bees  cleans  out  the  cells  after  the  young 
bees  are  born,  and  makes  them  fit  to  receive  honey,  while  others 
guard  the  entrance  of  the  hive  to  keep  away  the  destructive 
wax-moth,  which  tries  to  lay  its  eggs  in  the  comb  so  that  its 
young  ones  may  feed  on  the  honey.  All  industrious  people 
have  to  guard  their  property  against  thieves  and  vagabonds, 
and  the  bees  have  many  intruders,  such  as  wasps  and  snails  and 
slugs,  which  creep  in  whenever  they  get  a  chance.  If  they 
succeed  in  escaping  the  sentinel  bees,  then  a  fight  takes 
place  within  the  hive,  and  the  invader  is  stung  to  death. 

Sometimes,  however,  after  they  have  killed  the  enemy,  the 


356  ACHIEVEMENTS  IN  SCIENCE 

bees  cannot  get  rid  of  his  body,  for  a  snail  or  slug  is  too  heavy 
to  be  easily  moved,  and  yet  it  would  make  the  hive  very  un- 
healthy to  allow  it  to  remain.  In  this  dilemma  the  ingenious 
little  bees  fetch  the  gummy  "  propolis "  from  the  plant-buds 
and  cement  the  intruder  all  over,  thus  embalming  his  body  and 
preventing  it  from  decaying. 

And  so  the  life  of  this  wonderful  city  goes  on.  Building, 
harvesting,  storing,  nursing,  ventilating,  and  cleaning  from 
morn  till  night,  the  little  worker  bee  lives  for  about  eight 
months,  and  in  that  time  has  done  quite  her  share  of  work  in 
the  world.  Only  the  young  bees,  born  late  in  the  season,  live 
on  till  the  next  year  to  work  in  the  spring.  The  queen  bee 
lives  longer,  probably  about  two  years,  and  then  she,  too,  dies, 
after  having  had  a  family  of  many  thousands  of  children. 


EVOLUTION  AND  NATURE  STUDIES 


The  Massacre  of  the  Males 

From  the  "  Life  of  the  Bee  " 
By  M.  MAETERLINCK 

IF  skies  remain  clear,  the  air  warm,  and  pollen  and  nectar 
abound  in  the  flowers,  the  workers,  through  a  kind  of  for- 
getful indulgence,  or  over-scrupulous  prudence  perhaps,  will 
for  a  short  time  longer  endure  the  importunate,  disastrous  pres- 
ence of  the  males.  These  comport  themselves  in  the  hives  as 
did  Penelope's  suitors  in  the  house  of  Ulysses.  Indelicate  and 
wasteful,  sleek  and  corpulent,  fully  content  with  their  idle 
existence  as  honorary  lovers,  they  feast  and  carouse,  throng  the 
alleys,  obstruct  the  passages,  and  hinder  the  work;  jostling 
and  jostled,  fatuously  pompous,  swelled  with  foolish,  good- 
natured  contempt ;  harboring  never  a  suspicion  of  the  deep  and 
calculating  scorn  wherewith  the  workers  regard  them,  of  the 
constantly  growing  hatred  to  which  they  give  rise,  or  of  the 
destiny  that  awaits  them.  For  their  pleasant  slumbers  they 
select  the  snuggest  corners  of  the  hive ;  then,  rising  carelessly, 
they  flock  to  the  open  cells  where  the  honey  smells  sweetest. 
From  noon  till  three,  when  the  purple  country  trembles  in 
blissful  lassitude  beneath  the  invincible  gaze  of  a  July  or 
August  sun,  the  drones  will  appear  on  the  threshold.  They 
have  a  helmet  made  of  enormous  black  pearls,  two  lofty,  quiver- 
ing plumes,  a  doublet  of  iridescent,  yellowish  velvet,  an  heroic 
tuft,  and  a  fourfold  mantle,  translucent  and  rigid.  They  create 
a  prodigious  stir,  brush  the  sentry  aside,  overturn  the  cleaners, 
and  collide  with  the  foragers  as  these  return  laden  with  their 
humble  spoil.  They  have  the  busy  air,  the  extravagant,  con- 

357 


358  ACHIEVEMENTS  IN  SCIENCE 

temptuous  gait  of  indispensable  gods  who  should  be  simultane- 
ously venturing  towards  some  destiny  unknown  to  the  vulgar. 
One  by  one  they  sail  off  into  space,  irresistible,  glorious,  and 
tranquilly  make  for  the  nearest  flowers,  where  they  sleep  till 
the  afternoon  freshness  awakens  them.  Then,  with  the  same 
majestic  pomp,  and  still  overflowing  with  magnificent  schemes, 
they  return  to  the  hive,  go  straight  to  the  cells,  plunge  their 
head  to  the  neck  in  the  vats  of  honey,  and  fill  themselves  tight 
as  a  drum  to  repair  their  exhausted  strength ;  whereupon,  with 
heavy  steps,  they  go  forth  to  meet  the  good,  dreamless,  and 
careless  slumber  that  shall  fold  them  in  its  embrace  till  the 
time  for  the  next  repast. 

But  the  patience  of  the  bees  is  not  equal  to  that  of  men. 
One  morning  the  long-expected  word  of  command  goes  through 
the  hive;  and  the  peaceful  workers  turn  into  judges  and  execu- 
tioners. Whence  this  word  issues,  we  know  not;  it  would 
seem  to  emanate  suddenly  from  the  cold,  deliberate  indignation 
of  the  workers ;  and  no  sooner  has  it  been  uttered  than  every 
heart  throbs  with  it,  inspired  by  the  genius  of  the  unanimous 
republic.  One  part  of  the  people  renounce  their  foraging  duties 
to  devote  themselves  to  the  work  of  justice.  The  great  idle 
drones,  asleep  in  unconscious  groups  on  the  melliferous  walls, 
are  rudely  torn  from  their  slumbers  by  an  army  of  wrathful 
virgins.  They  wake,  in  pious  wonder;  they  cannot  believe 
their  eyes;  and  their  astonishment  struggles  through  their 
sloth  as  a  moonbeam  through  marshy  water.  They  stare 
amazedly  round  them,  convinced  that  they  must  be  victims  of 
some  mistake ;  and  the  mother-idea  of  their  life  being  first  to 
assert  itself  in  their  dull  brain,  they  take  a  step  toward  the 
vats  of  honey  to  seek  comfort  there.  But  ended  for  them  are 
the  days  of  May  honey,  the  wine-flower  of  lime-trees  and  fra- 
grant ambrosia  of  thyme  and  sage,  of  marjoram  and  white 
clover.  Where  the  path  once  lay  open  to  the  kindly,  abundant 
reservoirs,  that  so  invitingly  offered  their  waxen  and  sugary 
mouths,  there  stands  now  a  burning  bush  all  alive  with  poison- 
ous, bristling  stings.  The  atmosphere  of  the  city  is  changed ; 
in  lieu  of  the  friendly  perfume  of  honey,  the  acrid  odor  of  poi- 
son prevails ;  thousands  of  tiny  drops  glisten  at  the  end  of  the 


EVOLUTION  AND  NATURE  STUDIES          359 

stings,  and  diffuse  rancor  and  hatred.  Before  the  bewildered 
parasites  are  able  to  realize  that  the  happy  laws  of  the  city 
have  crumbled,  dragging  down  in  most  inconceivable  fashion 
their  own  plentiful  destiny,  each  one  is  assailed  by  three  or 
four  envoys  of  justice;  and  these  vigorously  proceed  to  cut  off 
his  wings,  saw  through  the  petiole  that  connects  the  abdomen 
with  the  thorax,  amputate  the  feverish  antennae,  and  seek  an 
opening  between  the  rings  of  his  cuirass  through  which  to  pass 
their  sword.  No  defense  is  attempted  by  the  enormous,  but 
unarmed  creatures ;  they  try  to  escape,  or  oppose  their  mere 
bulk  to  the  blows  that  rain  down  upon  them.  Forced  onto 
their  backs,  with  their  relentless  enemies  clinging  doggedly  to 
them,  they  will  use  their  powerful  claws  to  shift  them  from  side 
to  side;  or,  turning  on  themselves,  they  will  drag  the  whole 
group  round  and  round  in  wild  circles,  which  exhaustion  soon 
brings  to  an  end.  And,  in  a  very  brief  space,  their  appearance 
becomes  so  deplorable  that  pity,  never  far  from  justice  in  the 
depths  of  our  heart,  quickly  returns,  and  would  seek  forgive- 
ness, though  vainly,  of  the  stern  workers  who  recognize  only 
Nature's  harsh  and  profound  laws.  The  wings  of  the  wretched 
creatures  are  torn,  their  antennae  bitten,  the  segments  of  their 
legs  wrenched  off ;  and  their  magnificent  eyes,  once  mirrors  of 
the  exuberant  flowers,  flashing  back  the  blue  light  and  the  in- 
nocent pride  of  summer,  now,  softened  by  suffering,  reflect 
only  the  anguish  and  distress  of  their  end.  Some  succumb  to 
their  wounds,  and  are  at  once  borne  away  to  distant  cemeteries 
by  two  or  three  of  their  executioners.  Others,  whose  injuries 
are  less,  succeed  in  sheltering  themselves  in  some  corner, 
where  they  lie,  all  huddled  together,  surrounded  by  an  inexora- 
ble guard,  until  they  perish  of  want.  Many  will  reach  the 
door,  and  escape  into  space,  dragging  their  adversaries  with 
them ;  but,  toward  evening,  impelled  by  hunger  and  cold,  they 
return  in  crowds  to  the  entrance  of  the  hive  to  beg  for  shelter. 
But  there  they  encounter  another  pitiless  guard.  The  next 
morning,  before  setting  forth  on  their  journey,  the  workers 
will  clear  the  threshold,  strewn  with  the  corpses  of  the  useless 
giants ;  and  all  recollection  of  the  idle  race  disappears  till  the 
following  spring. 


EVOLUTION  AND  NATURE  STUDIES 


White  Ants 

By  HENRY  DRUMMOND 

THE  termite  or  white  ant  is  a  small  insect,  with  a  bloated, 
yellowish-white  body,  and  a  somewhat  large  thorax,  ob- 
long-shaped, and  colored  a  disagreeable  oily  brown.  The  flabby, 
tallow-like  body  makes  this  insect  sufficiently  repulsive,  but  it 
is  for  quite  another  reason  that  the  white  ant  is  the  worst 
abused  of  all  living  vermin  in  warm  countries.  The  termite 
lives  almost  exclusively  upon  wood ;  and  the  moment  a  tree  is 
cut  or  a  log  sawed  for  any  economical  purpose,  this  insect  is 
upon  its  track.  One  may  never  see  the  insect,  possibly,  in  the 
flesh,  for  it  lives  underground ;  but  its  ravages  confront  one  at 
every  turn.  You  build  your  house,  perhaps,  and  for  a  few 
months  fancy  you  have  pitched  upon  the  one  solitary  site  in 
the  country  where  there  are  no  white  ants.  But  one  day  sud- 
denly the  door-post  totters,  and  lintel  and  rafters  come  down 
together  with  a  crash.  You  look  at  a  section  of  the  wrecked 
timbers,  and  discover  that  the  whole  inside  is  eaten  clean  away. 
The  apparently  solid  logs  of  which  the  rest  of  the  house  is  built 
are  now  mere  cylinders  of  bark,  and  through  the  thickest  of 
them  you  could  push  your  little  finger.  Furniture,  tables,  chairs, 
chests  of  drawers,  everything  made  of  wood,  is  inevitably  at- 
tacked, and  in  a  single  night  a  strong  trunk  is  often  riddled 
through  and  through,  and  turned  into  matchwood.  There  is  no 
limit,  in  fact,  to  the  depredation  by  these  insects,  and  they  will 
eat  books,  or  leather,  or  cloth,  or  anything ;  and  in  many  parts 
of  Africa  I  believe  if  a  man  lay  down  to  sleep  with  a  wooden 
leg,  it  would  be  a  heap  of  sawdust  in  the  morning.  So  much 

360 


EVOLUTION  AND  NATURE  STUDIES          361 

feared  is  this  insect  now,  that  no  one  in  certain  parts  of  India 
and  Africa  ever  attempts  to  travel  with  such  a  thing  as  a 
wooden  trunk.  On  the  Tanganyika  plateau  I  have  camped  on 
ground  which  was  as  hard  as  adamant,  and,  apparently,  as  inno- 
cent of  white  ants  as  the  pavement  of  St.  Paul's ;  and  wakened 
next  morning  to  find  a  stout  wooden  box  almost  gnawed  to 
pieces.  Leather  portmanteaus  share  the  same  fate,  and  the  only 
substances  which  seem  to  defy  the  marauders  are  iron  and  tin. 

But  what  has  this  to  do  with  earth  or  with  agriculture  ? 
The  most  important  point  in  the  work  of  the  white  ant  remains 
to  be  noted.  I  have  already  said  that  the  white  ant  is  never 
seen.  Why  he  should  have  such  a  repugnance  to  being  looked 
at  is  at  first  sight  a  mystery,  seeing  that  he  himself  is  stone 
blind.  But  his  coyness  is  really  due  to  the  desire  for  self-pro- 
tection; for  the  moment  his  juicy  body  shows  itself  above 
ground,  there  are  a  dozen  enemies  waiting  to  devour  it.  And 
yet  the  white  ant  can  never  procure  any  food  until  it  comes 
above  ground.  Nor  will  it  meet  the  case  for  the  insect  to  come 
to  the  surface  under  the  shadow  of  night.  Night  in  the  tropics, 
so  far  as  animal  life  is  concerned,  is  as  the  day.  It  is  the  great 
feeding-time,  the  great  fighting-time,  the  carnival  of  the  carni- 
vora,  and  of  all  beasts,  birds,  and  insects  of  prey,  from  the  least 
to  the  greatest.  It  is  clear  then  that  darkness  is  no  protection 
to  the  white  ant ;  and  yet  without  coming  out  of  the  ground  it 
cannot  live.  How  does  it  solve  the  difficulty  ?  It  takes  the 
ground  out  along  with  it.  I  have  seen  white  ants  working  on 
the  top  of  a  high  tree,  and  yet  they  were  underground.  They 
took  up  some  of  the  ground  with  them  to  the  tree-top;  just  as 
the  Esquimaux  heap  up  snow,  building  it  into  the  low  tunnel- 
huts  in  which  they  live,  so  the  white  ants  collect  earth,  only  in 
this  case  not  from  the  surface,  but  from  some  depth  underneath 
the  ground,  and  plaster  it  into  tunneled  ways.  Occasionally 
these  run  along  the  ground,  but  more  often  mount  in  endless 
ramifications  to  the  top  of  trees,  meandering  along  every  branch 
and  twig,  and  here  and  there  debouching  into  large  covered 
chambers  which  occupy  half  the  girth  of  the  trunk.  Millions  of 
trees  in  some  districts  are  thus  fantastically  plastered  over  with 
tubes,  galleries,  and  chambers  of  earth,  and  many  pounds' 


362  ACHIEVEMENTS  IN  SCIENCE 

weight  of  subsoil  must  be  brought  up  for  the  mining  of  even  a 
single  tree.  The  building  material  is  conveyed  by  the  insects 
up  a  central  pipe  with  which  all  the  galleries  communicate,  and 
which  at  the  downward  end  connects  with  a  series  of  subterra- 
nean passages  leading  deep  into  the  earth.  The  method  of 
building  the  tunnels  and  covered  ways  is  as  follows :  At  the 
foot  of  a  tree  the  tiniest  hole  cautiously  opens  in  the  ground 
close  to  the  bark.  A  small  head  appears,  with  a  grain  of  earth 
clasped  in  its  jaws.  Against  the  tree  trunk  this  earth-grain  is 
deposited,  and  the  head  is  withdrawn.  Presently  it  reappears 
with  another  grain  of  earth ;  this  is  laid  beside  the  first,  rammed 
tight  against  it,  and  again  the  builder  descends  underground 
for  more.  The  third  grain  is  not  placed  against  the  tree,  but 
against  the  former  grain ;  a  fourth,  a  fifth,  and  a  sixth  follow, 
and  the  plan  of  the  foundation  begins  to  suggest  itself  as  soon 
as  these  are  in  position.  The  stones,  or  grains,  or  pellets  of 
earth  are  arranged  in  a  semicircular  wall;  the  termite,  now 
assisted  by  three  or  four  others,  standing  in  the  middle  between 
the  sheltering  wall  and  the  tree,  and  working  briskly  with  head 
and  mandible  to  strengthen  the  position.  The  wall  in  fact 
forms  a  small  moon-rampart,  and  as  it  grows  higher  and  higher 
it  soon  becomes  evident  that  it  is  going  to  grow  from  a  low 
battlement  into  a  long  perpendicular  tunnel  running  up  the  side 
of  the  tree.  The  workers,  safely  ensconced  inside,  are  now 
carrying  up  the  structure  with  great  rapidity,  disappearing  in 
turn  as  soon  as  they  have  laid  their  stone,  and  rushing  off  to 
bring  up  another.  The  way  in  which  the  building  is  done  is 
extremely  curious,  and  one  could  watch  the  movements  of 
these  wonderful  little  masons  by  the  hour.  Each  stone  as  it  is 
brought  to  the  top  is  first  of  all  covered  with  mortar.  Of 
course,  without  this  the  whole  tunnel  would  crumble  into  dust 
before  reaching  the  height  of  half  an  inch ;  but  the  termite 
pours  over  the  stone  a  moist,  sticky  secretion,  turning  the  grain 
round  and  round  with  its  mandibles  until  the  whole  is  covered 
with  slime.  Then  it  places  the  stone  with  great  care  upon  the 
top  of  the  wall,  works  it  about  vigorously  for  a  moment  or  two 
till  it  is  well  jammed  into  its  place,  and  then  starts  off  instantly 
for  another  load. 


EVOLUTION  AND  NATURE  STUDIES          363 

Peering  over  the  growing  wall,  one  soon  discovers  one,  two, 
or  more  termites  of  a  somewhat  larger  build,  considerably 
longer,  and  with  a  very  different  arrangement  of  the  parts  of 
the  head,  and  especially  of  the  mandibles.  These  important- 
looking  individuals  saunter  about  the  rampart  in  the  most 
leisurely  way,  but  yet  with  a  certain  air  of  business,  as  if  per- 
haps the  one  was  the  master  of  works  and  the  other  the  archi- 
tect. But  closer  observation  suggests  that  they  are  in  nowise 
superintending  operations,  nor  in  any  immediate  way  contribut- 
ing to  the  structure,  for  they  take  not  the  slightest  notice 
either  of  the  workers  or  the  works.  They  are  posted  there  in 
fact  as  sentries;  and  there  they  stand,  or  promenade  about,  at 
the  mouth  of  every  tunnel,  like  Sister  Anne,  to  see  if  anybody 
is  coming.  Sometimes  somebody  does  come,  in  the  shape  of 
another  ant ;  the  real  ant  this  time,  not  the  defenseless  Neurop- 
teron,  but  some  valiant  and  belted  knight  from  the  warlike 
Formicida.  Singly  or  in  troops,  this  rapacious  little  insect, 
fearless  in  its  chitinous  coat  of  mail,  charges  down  the  tree 
trunk,  its  antennae  waving  defiance  to  the  enemy  and  its  cruel 
mandibles  thirsting  for  termite  blood.  The  worker  white-ant 
is  a  poor,  defenseless  creature,  and,  blind  and  unarmed,  would 
fall  an  immediate  prey  to  these  well-drilled  banditti,  who  forage 
about  in  every  tropical  forest  in  unnumbered  legion.  But  at 
the  critical  moment,  like  Goliath  from  the  Philistines,  the  soldier 
termite  advances  to  the  fight.  With  a  few  sweeps  of  its  scythe- 
like  jaws,  it  clears  the  ground,  and  while  the  attacking  party  is 
carrying  off  its  dead,  the  builders,  unconscious  of  the  fray, 
quietly  continue  their  work.  To  every  hundred  workers  in  a 
white-ant  colony,  which  numbers  many  thousands  of  individuals, 
there  are  perhaps  two  of  these  fighting-men.  The  division  of 
labor  here  is  very  wonderful ;  and  the  fact  that  besides  these 
two  specialized  forms  there  are  in  every  nest  two  other  kinds 
of  the  same  insect,  the  kings  and  queens,  shows  the  remarka- 
ble height  to  which  civilization  in  these  communities  has 
attained. 

But  where  is  this  tunnel  going  to,  and  what  object  have  the 
insects  in  view  in  ascending  this  lofty  tree  ?  Thirty  feet  from 
the  ground,  across  innumerable  forks,  at  the  end  of  a  long 


364  ACHIEVEMENTS  IN  SCIENCE 

branch,  are  a  few  feet  of  dead  wood.  How  the  ants  know  it  is 
there,  how  they  know  its  sap  has  dried  up,  and  that  it  is  now 
fit  for  the  termites'  food,  is  a  mystery.  Possibly  they  do  not 
know  and  are  only  prospecting  on  the  chance.  The  fact  that 
they  sometimes  make  straight  for  the  decaying  limb  argues,  in 
these  instances,  a  kind  of  definite  instinct ;  but,  on  the  other 
hand,  the  fact  that  in  most  cases  the  whole  tree,  in  every  branch 
and  limb,  is  covered  with  termite  tunnels,  would  show  perhaps 
that  they  work  most  commonly  on  speculation,  while  the  num- 
ber of  abandoned  tunnels,  ending  on  a  sound  branch  in  a  cut  de 
sac,  proves  how  often  they  must  suffer  the  usual  disappoint- 
ments of  all  such  adventurers.  The  extent  to  which  these 
insects  carry  on  their  tunneling  is  quite  incredible,  until  one 
has  seen  it  in  nature  with  his  own  eyes.  The  tunnels  are  per- 
haps about  the  thickness  of  a  small-sized  gas-pipe,  but  there  are 
junctions  here  and  there  of  large  dimensions,  and  occasionally 
patches  of  earth -work  are  found,  embracing  nearly  the  whole 
trunk  for  some  feet.  The  outside  of  these  tunnels,  which  are 
never  quite  straight,  but  wander  irregularly  along  stem  and 
branch,  resembles  in  texture  a  coarse  sandpaper ;  and  the  color, 
although  this  naturally  varies  with  the  soil,  is  usually  a  reddish 
brown.  The  quantity  of  earth  and  mud  plastered  over  a  single 
tree  is  often  enormous ;  and  when  one  thinks  that  it  is  not  only 
an  isolated  specimen  here  and  there  that  is  frescoed  in  this 
way,  but  often  all  the  trees  of  a  forest,  some  idea  will  be  formed 
of  the  magnitude  of  the  operations  of  these  insects,  and  the  ex- 
tent of  their  influence  upon  the  soil  which  they  are  ceaselessly 
transporting  from  underneath  the  ground. 

In  traveling  through  the  great  forests  of  the  Rocky  Moun- 
tains or  of  the  Western  States,  the  broken  branches  and  fallen 
trunks,  strewing  the  ground  breast-high  with  all  sorts  of  decay- 
ing litter,  frequently  make  locomotion  impossible.  To  attempt 
to  ride  through  these  western  forests,  with  their  meshwork  of 
interlocked  branches  and  decaying  trunks,  is  often  out  of  the 
question,  and  one  has  to  dismount  and  drag  his  horse  after  him 
as  if  he  were  clambering  through  a  wood-yard.  But  in  an  Afri- 
can forest  not  a  fallen  branch  is  seen.  One  is  struck  at  first 
by  a  certain  clean  look  about  the  great  forests  of  the  interior,  a 


EVOLUTION  AND  NATURE  STUDIES          365 

novel  and  unaccountable  cleanness,  as  if  the  forest  bed  was 
carefully  swept  and  dusted  daily  by  unseen  elves.  And  so  in- 
deed it  is.  Scavengers  of  a  hundred  kinds  remove  decaying 
animal  matter,  from  the  carcass  of  a  fallen  elephant  to  the 
broken  wing  of  a  gnat ;  eating  it,  or  carrying  it  out  of  sight  and 
burying  it  in  the  deodorizing  earth.  And  these  countless  mil- 
lions of  termites  perform  a  similar  function  for  the  vegetable 
world,  making  away  with  all  plants  and  trees,  all  stems,  twigs, 
and  tissues,  the  moment  the  ringer  of  decay  strikes  the  signal. 
Constantly,  in  these  woods,  one  comes  across  what  appear  to 
be  sticks  and  branches  and  bundles  of  fagots,  but  when  closely 
examined,  they  are  seen  to  be  mere  casts  in  mud.  From  these 
hollow  tubes,  which  preserve  the  original  form  of  the  branch 
down  to  the  minutest  knot  or  fork,  the  ligneous  tissue  is  often 
entirely  removed,  while  others  are  met  with  in  all  stages  of 
demolition.  There  is  the  section  of  an  actual  specimen,  which 
is  not  yet  completely  destroyed,  and  from  which  the  mode  of 
attack  may  be  easily  seen.  The  insects  start  apparently  from 
two  centers.  One  company  attacks  the  inner  bark,  which  is 
the  favorite  morsel,  leaving  the  coarse  outer  bark  untouched, 
or  more  usually  replacing  it  with  grains  of  earth,  atom  by  atom, 
as  they  eat  it  away.  The  inner  bark  is  gnawed  off  likewise  as 
they  go  along,  but  the  woody  tissue  beneath  is  allowed  to  re- 
main, to  form  a  protective  sheath  for  the  second  company,  who 
begin  work  at  the  center.  This  second  contingent  eats  its  way 
outward  and  onward,  leaving  a  thin  tube  of  the  outer  wood  to 
the  last,  as  props  to  the  mine,  till  they  have  finished  the  main 
excavation.  When  a  fallen  trunk  lying  upon  the  ground  is  the 
object  of  attack,  the  outer  cylinder  is  frequently  left  quite  in- 
tact, and  it  is  only  when  one  tries  to  drag  it  off  to  his  camp-fire 
that  he  finds  to  his  disgust  that  he  is  dealing  with  a  mere  hol- 
low tube,  a  few  lines  in  thickness,  filled  up  with  mud. 

But  the  works  above-ground  represent  only  a  part  of  the 
labors  of  these  slow-moving  but  most  industrious  of  creatures. 
The  arboreal  tubes  are  only  the  prolongation  of  a  much  more 
elaborate  system  of  subterranean  tunnels,  which  extend  over 
large  areas,  and  mine  the  earth  sometimes  to  a  depth  of  many 
feet  or  even  yards. 


366  ACHIEVEMENTS  IN  SCIENCE 

The  material  excavated  from  these  underground  galleries 
and  from  the  succession  of  domed  chambers— used  as  nurseries 
or  granaries — to  which  they  lead,  has  to  be  thrown  out  upon 
the  surface.  And  it  is  from  these  materials  that  the  huge  ant- 
hills are  reared,  which  form  so  distinctive  a  feature  of  the  Afri- 
can landscape.  These  heaps  and  mounds  are  so  conspicuous 
that  they  may  be  seen  for  miles,  and  so  numerous  are  they, 
and  so  useful  as  cover  to  the  sportsman,  that,  without  them,  in 
certain  districts  hunting  would  be  impossible.  The  first  things, 
indeed,  to  strike  the  traveler  in  entering  the  interior  are  the 
mounds  of  the  white  ant,  now  dotting  the  plain  in  groups  like 
a  small  cemetery,  now  rising  into  mounds,  singly  or  in  clusters, 
each  thirty  or  forty  feet  in  diameter  and  ten  or  fifteen  in  height ; 
or  again  standing  out  against  the  sky  like  obelisks,  their  bare 
sides  carved  and  fluted  into  all  sorts  of  fantastic  shapes.  In 
India  these  ant-heaps  seldom  attain  a  height  of  more  than  a 
couple  of  feet,  but  in  Central  Africa  they  form  veritable  hills, 
and  contain  many  tons  of  earth.  The  brick  houses  of  the 
Scotch  mission-station  on  Lake  Nyassa  have  all  been  built  out 
of  a  single  ant's  nest,  and  the  quarry  from  which  the  material 
has  been  derived  forms  a  pit  beside  the  settlement  some  dozen 
feet  in  depth.  A  supply  of  bricks  as  large  again  could  proba- 
bly still  be  taken  from  this  convenient  depot ;  and  the  missiona- 
ries on  Lake  Tanganyika  and  onward  to  Victoria  Nyanza  have 
been  similarly  indebted  to  the  labors  of  the  termites.  In  South 
Africa  the  Zulus  and  Kaffirs  pave  all  their  huts  with  white- 
ant  earth ;  and  during  the  Boer  war  our  troops  in  Pretoria,  by 
scooping  out  the  interior  from  the  smaller  beehive-shaped  ant- 
heaps  and  covering  the  top  with  clay,  constantly  used  them  as 
ovens.  These  ant-heaps  may  be  said  to  abound  over  the  whole 
interior  of  Africa,  and  there  are  several  distinct  species.  The 
most  peculiar,  as  well  as  the  most  ornate,  is  a  small  variety 
from  one  to  two  feet  in  height,  which  occurs  in  myriads  along 
the  shores  of  Lake  Tanganyika.  It  is  built  in  symmetrical 
tiers,  and  resembles  a  pile  of  small  rounded  hats,  one  above 
another,  the  rims  depending  like  eaves,  and  sheltering  the  body 
of  the  hill  from  rain.  To  estimate  the  amount  of  earth  per 
acre  raised  from  the  water-line  of  the  subsoil  by  white  ants, 


EVOLUTION  AND  NATURE  STUDIES          367 

would  not  in  some  districts  be  an  impossible  task,  and  it  would 
probably  be  found  that  the  quantity  at  least  equaled  that 
manipulated  in  temperate  regions  by  the  earthworm. 

These  mounds,  however,  are  more  than  mere  waste-heaps. 
Like  the  corresponding  region  underground,  they  are  built  into 
a  meshwork  of  tunnels,  galleries,  and  chambers,  where  the 
social  interests  of  the  community  are  attended  to.  The  most 
spacious  of  these  chambers,  usually  far  underground,  is  very 
properly  allocated  to  the  head  of  the  society,  the  queen.  The 
queen  termite  is  a  very  rare  insect,  and  as  there  are  seldom 
more  than  one,  or  at  most  two,  to  a  colony,  and  as  the  royal 
apartments  are  hidden  far  in  the  earth,  few  persons  have  ever 
seen  a  queen ;  and  indeed  most,  if  they  did  happen  to  come 
across  it,  from  its  very  singular  appearance,  would  refuse  to 
believe  that  it  had  any  connection  with  white  ants.  It  pos- 
sesses indeed  the  true  termite  head,  but  there  the  resemblance 
to  the  other  members  of  the  family  stops ;  for  the  size  of  the 
head  bears  about  the  same  proportion  to  the  rest  of  the  body 
as  does  the  tuft  on  his  Glengarry  bonnet  to  a  six-foot  High- 
lander. The  phenomenal  corpulence  of  the  royal  body  in  the 
case  of  the  queen  termite  is  possibly  due  in  part  to  want  of  ex- 
ercise ;  for,  once  seated  upon  her  throne,  she  never  stirs  to  the 
end  of  her  days.  She  lies  there,  a  large,  loathsome,  cylindrical 
package,  two  or  three  inches  long,  in  shape  like  a  sausage,  and 
as  white  as  a  bolster.  Her  one  duty  in  life  is  to  lay  eggs ;  and  it 
must  be  confessed  she  discharges  her  function  with  complete 
success,  for  in  a  single  day  her  progeny  often  amounts  to  many 
thousands,  and  for  months  this  enormous  fecundity  never 
slackens.  The  body  increases  slowly  in  size,  and  through  the 
transparent  skin  the  long  folded  ovary  may  be  seen,  with  the 
iggs,  impelled  by  a  peristaltic  motion,  passing  onward  for  de- 
livery to  the  workers,  who  are  waiting  to  carry  them  to  the 
nurseries,  where  they  are  hatched.  Assiduous  attention,  mean- 
time, is  paid  to  the  queen  by  other  workers,  who  feed  her  dili- 
gently, with  much  self-denial,  stuffing  her  with  morsel  after 
lorsel  from  their  own  jaws.  A  guard  of  honor  in  the  shape 
of  a  few  of  the  larger  soldier  ants  is  also  in  attendance,  as  a  last 
and  almost  unnecessary  precaution.  In  addition  finally,  to  the 


368  ACHIEVEMENTS  IN  SCIENCE 

soldiers,  workers,  and  queen,  the  royal  chamber  has  also  one 
other  inmate — the  king.  He  is  a  very  ordinary-looking  insect, 
about  the  same  size  as  the  soldiers,  but  the  arrangement  of  the 
parts  of  the  head  and  body  is  widely  different,  and,  like  the 
queen,  he  is  furnished  with  eyes. 


EVOLUTION  AND  NATURE  STUDIES 


The  Habits  of  Ants 

By  SIR  JOHN  LUBBOCK 

THE  communities  of  ants  are  sometimes  very  large,  num- 
bering even  up  to  500,000  individuals ;  and  it  is  a  lesson 
to  us,  that  no  one  has  ever  yet  seen  a  quarrel  between  any  two 
ants  belonging  to  the  same  community.  On  the  other  hand, 
it  must  be  admitted  that  they  are  in  hostility  not  only  with 
most  other  insects,  including  ants  of  different  species,  but  even 
with  those  of  the  same  species,  if  belonging  to  different  com- 
munities. I  have  over  and  over  again  introduced  ants  from  one 
of  my  nests  into  another  nest  of  the  same  species ;  and  they 
were  invariably  attacked,  seized  by  a  leg  or  an  antenna,  and 
dragged  out. 

It  is  evident,  therefore,  that  the  ants  of  each  community  all 
recognize  one  another,  which  is  very  remarkable.  But  more 
than  this,  I  have  several  times  divided  a  nest  into  two  halves, 
and  found  that  even  after  a  separation  of  a  year  and  nine 
months  they  recognized  one  another,  and  were  perfectly 
friendly ;  while  they  at  once  attacked  ants  from  a  different 
nest,  although  of  the  same  species. 

It  has  been  suggested  that  the  ants  of  each  nest  have  some 
sign  or  password  by  which  they  recognize  one  another.  To 
test  this  I  made  some  insensible.  First  I  tried  chloroform; 
but  this  was  fatal  to  them,  and  I  did  not  consider  the  test  satis- 
factory. I  decided  therefore  to  intoxicate  them.  This  was 
less  easy  than  I  had  expected.  None  of  my  ants  would  volun- 
tarily degrade  themselves  by  getting  drunk.  I  got  over  the 
difficulty,  however,  by  putting  them  into  whisky  for  a  few 
24  369 


370  ACHIEVEMENTS  IN  SCIENCE 

moments.  I  took  fifty  specimens — twenty-five  from  one  nest 
and  twenty-five  from  another — made  them  dead  drunk,  marked 
each  with  a  spot  of  paint,  and  put  them  on  a  table  close  to 
where  other  ants  from  one  of  the  nests  were  feeding.  The 
table  was  surrounded  as  usual  with  a  moat  of  water  to  prevent 
them  from  straying.  The  ants  which  were  feeding  soon  noticed 
those  which  I  had  made  drunk.  They  seemed  quite  astonished 
to  find  their  comrades  in  such  a  disgraceful  condition,  and  as 
much  at  a  loss  to  know  what  to  do  with  their  drunkards  as  we 
are.  After  a  while,  however,  to  cut  my  story  short,  they  car- 
ried them  all  away ;  the  strangers  they  took  to  the  edge  of  the 
moat  and  dropped  into  the  water,  while  they  bore  their  friends 
home  into  the  nest,  where  by  degrees  they  slept  off  the  effects 
of  the  spirit.  Thus  it  is  evident  that  they  know  their  friends 
even  when  incapable  of  giving  any  sign  or  password. 

This  little  experiment  also  shows  that  they  help  comrades 
in  distress.  If  a  wolf  or  a  rook  be  ill  or  injured,  we  are  told 
that  it  is  driven  away  or  even  killed  by  its  comrades.  Not  so 
with  ants.  For  instance,  in  one  of  my  nests  an  unfortunate 
ant,  in  emerging  from  the  chrysalis  skin,  injured  her  legs  so 
much  that  she  lay  on  her  back  quite  helpless.  For  three 
months,  however,  she  was  carefully  fed  and  tended  by  the  other 
ants.  In  another  case,  an  ant  had  injured  her  antennae  in  the 
same  manner.  I  watched  her  also  carefully  to  see  what  would 
happen.  For  some  days  she  did  not  leave  the  nest.  At  last 
one  day  she  ventured  outside,  and  after  a  while  met  a  stranger 
ant  of  the  same  species,  but  belonging  to  another  nest,  by 
whom  she  was  at  once  attacked.  I  tried  to  separate  them ;  but, 
whether  by  her  enemy  or,  perhaps,  by  my  well-meant  but  clumsy 
kindness,  she  was  evidently  much  hurt,  and  lay  helplessly  on 
her  side.  Several  other  ants  passed  her  without  taking  any 
notice ;  but  soon  one  came  up,  examined  her  carefully  with  her 
antennae,  and  carried  her  off  tenderly  to  the  nest.  No  one,  I 
think,  who  saw  it  could  have  denied  to  that  ant  one  attribute  of 
humanity,  the  quality  of  kindness. 

The  existence  of  such  communities  as  those  of  ants  or  bees 
implies,  no  doubt,  some  power  of  communication;  but  the 
amount  is  still  a  matter  of  doubt.  It  is  well  known  that  if  one 


i 


EVOLUTION  AND  NATURE  STUDIES          371 

bee  or  ant  discovers  a  store  of  food,  others  soon  find  their  way 
to  it.  This,  however,  does  not  prove  much.  It  makes  all  the 
difference  whether  they  are  brought  or  sent.  If  they  merely 
accompany,  on  her  return,  a  companion  who  has  brought  a  store 
of  food,  it  does  not  imply  much.  To  test  this,  therefore,  I 
made  several  experiments.  For  instance,  one  cold  day  my  ants 
were  almost  all  in  their  nests.  One  only  was  out  hunting,  and 
about  six  feet  from  home.  I  took  a  dead  bluebottle  fly,  pinned 
it  onto  a  piece  of  cork,  and  put  it  down  just  in  front  of  her. 
She  at  once  tried  to  carry  off  the  fly,  but  to  her  surprise  found 
it  immovable.  She  tugged  and  tugged,  first  one  way  and  then 
another,  for  about  twenty  minutes,  and  then  went  straight  off 
to  the  nest.  During  that  time  not  a  single  ant  had  come  out ; 
in  fact,  she  was  the  only  ant  of  that  nest  out  at  the  time.  She 
went  straight  in ;  but  in  a  few  seconds — less  than  half  a  minute 
—came  out  again  with  no  less  than  twelve  friends,  who  trooped 
off  with  her,  and  eventually  tore  up  the  dead  fly,  carrying  it  off 
in  triumph. 

Now,  the  first  ant  took  nothing  home  with  her;  she  must 
therefore  somehow  have  made  her  friends  understand  that  she 
had  found  some  food,  and  wanted  them  to  come  and  help  her 
to  secure  it.  In  all  such  cases,  however,  so  far  as  my  experi- 
ence goes,  the  ants  brought  their  friends ;  and  some  of  my  ex- 
periments indicated  that  they  are  unable  to  send  them. 

Certain  species  of  ants,  again,  make  slaves  of  others,  as 
Huber  first  observed.  If  a  colony  of  the  slave-making  ants  is 
changing  the  nest — a  matter  which  is  left  to  the  discretion  of 
the  slaves — the  latter  carry  their  mistresses  to  their  new  home. 
Again,  if  I  uncovered  one  of  my  nests  of  the  fuscous  ant  (For- 
mica fusca),  they  all  began  running  about  in  search  of  some 
place  of  refuge.  If  now  I  covered  over  one  small  part  of  the 
nest,  after  a  while  some  ant  discovered  it.  In  such  a  case, 
however,  the  brave  little  insect  never  remained  there;  she 
came  out  in  search  of  her  friends,  and  the  first  one  she  met  she 
took  up  in  her  jaws,  threw  over  her  shoulder  (their  way  of  car- 
rying friends),  and  took  into  the  covered  part ;  then  both  came 
out  again,  found  two  more  friends  and  brought  them  in,  the 
same  maneuver  being  repeated  until  the  whole  community  was 


372  ACHIEVEMENTS  IN  SCIENCE 

in  a  place  of  safety.  This,  I  think,  says  much  for  their  public 
spirit ;  but  seems  to  prove  that  —  in  F.  fusca  at  least  —  the 
powers  of  communication  are  but  limited. 

One  kind  of  slave-making  ant  has  become  so  completely  de- 
pendent on  their  slaves,  that  even  if  provided  with  food  they 
will  die  of  hunger,  unless  there  is  a  slave  to  put  it  into  their 
mouths.  I  found,  however,  that  they  would  thrive  very  well  if 
supplied  with  a  slave  for  an  hour  or  so  once  a  week  to  clean 
and  feed  them. 

But  in  many  cases  the  community  does  not  consist  of  ants 
only.  They  have  domestic  animals ;  and  indeed  it  is  not  going 
too  far  to  say  that  they  have  domesticated  more  animals  than 
we  have.  Of  these  the  most  important  are  aphides.  Some 
species  keep  aphides  on  trees  and  bushes,  others  collect  root- 
feeding  aphides  into  their  nests.  They  serve  as  cows  to  the 
ants,  which  feed  on  the  honey-dew  secreted  by  the  aphides. 
Moreover  the  ants  not  only  protect  the  aphides  themselves,  but 
also  collect  their  eggs  in  autumn  and  tend  them  carefully 
through  the  winter,  ready  for  the  next  spring.  Of  the  other 
insects  domesticated  by  ants  some,  from  living  constantly  under- 
ground, have  completely  lost  their  eyes  and  become  quite  blind. 

But  I  must  not  let  myself  be  carried  away  by  this  fascinat- 
ing subject,  which  I  have  treated  more  at  length  in  another 
work.  I  will  only  say  that  though  their  intelligence  is  no  doubt 
limited,  still  I  do  not  think  that  any  one  who  has  studied  the 
life-history  of  ants  can  draw  any  fundamental  line  of  separation 
between  instinct  and  reason. 

When  we  see  a  community  of  ants  working  together  in  per- 
fect harmony,  it  is  impossible  not  to  ask  ourselves  how  far  they 
are  mere  exquisite  automatons,  how  far  they  are  conscious 
beings.  When  we  watch  an  ant-hill  tenanted  by  thousands  of 
industrious  inhabitants,  excavating  chambers,  forming  tunnels, 
making  roads,  guarding  their  home,  gathering  food,  feeding  the 
young,  tending  their  domestic  animals — each  one  fulfilling  its 
duties  industriously,  and  without  confusion — it  is  difficult  alto- 
gether to  deny  to  them  the  gift  of  reason ;  and  all  our  recent  ob- 
servations tend  to  confirm  the  opinion  that  their  mental  powers 
differ  from  those  of  men  not  so  much  in  kind  as  in  degree. 


; 


EVOLUTION  AND  NATURE  STUDIES 


Spiders  and  Their  Ways 

By  MARGARET  WENTWORTH  LEIGHTON 

Spider, 

At  my  window  spinning, 

Weaving  circles  wider,  wider, 

From  the  deft  beginning ; 

Running 

Rings  and  spokes,  until  you 
Build  your  silken  death-trap  cunning — 
Shall  I  catch  you — kill  you? 

Sprawling, 

Nimble,  shrewd  as  Circe ; 
Death's  your  only  aim  and  calling, 
Why  should  you  have  mercy? 

Strike  thee? 
Not  for  rapine  willful : 
Man  himself  is  too  much  like  thee, 
Only  not  so  skillful. 

— GEORGE  HORTON'S  Songs  of  the  Lowly. 

NOT  so  skillful,  and  doubtless  never  will  be,  for  to-day  a 
spider's  thread  is  used  in  the  telescope  because  man  has 
been  unable  to  manufacture  one  so  fine  and  delicate. 

Whenever  I  look  at  the  marvelous  web  of  the  great  black- 
and-gold  garden  spider  I  remember  that  pretty  story  of  the 
way  in  which  the  group  of  spiders  received  its  name  of  Arach- 
nid<z.  In  the  olden  times  there  was  a  lovely  maiden  named 

373 


374  ACHIEVEMENTS  IN  SCIENCE 

Arachne,  who  could  weave  and  embroider  with  such  deftness 
that  the  nymphs  all  gathered  to  watch  her.  They  whispered 
to  each  other  that  she  must  have  been  taught  by  Minerva  her- 
self, who  was  the  goddess  of  Wisdom.  Arachne  overheard 
them,  and,  denying  their  accusation,  challenged  Minerva  to  a 
trial  of  skill.  Minerva  accepted  the  challenge,  and  when  the 
webs  were  woven  Arachne' s  was  wonderfully  beautiful,  but 
Minerva's  far  surpassed  it.  Arachne  was  in  despair  and  hung 
herself,  whereupon  Minerva's  chagrin  was  so  great  that  she 
transformed  her  into  a  spider,  and  her  descendants  preserve 
much  of  her  skill. 

We  are  apt  to  think  of  spiders  as  insects,  but  really  they 
are  only  distantly  related  to  insects,  their  first  cousins  being 
scorpions  and  king  crabs.  The  spider's  body  consists  of  two 
parts.  It  has  four  pairs  of  legs,  a  pair  of  palpi,  and  a  pair  of 
mandibles.  The  legs  are  jointed,  and  on  the  last  joint  there 
are  three  claws.  The  palpi  are  used  as  feelers  and  to  hold  the 
food.  The  breathing  apparatus  of  the  spider  is  a  combination 
of  lungs  and  gills.  It  has  glands  containing  poison  which  lie 
partly  in  the  head  and  partly  in  the  basal  joint  of  the  mandi- 
bles. There  is  a  tiny  opening  in  the  claw  on  the  mandible, 
out  of  which  the  poison  flows  when  the  spider  captures  its  prey. 
It  has  eight  eyes.  The  spiders  are  classified  largely  by  the 
different  arrangements  and  grouping  of  the  eyes.  Some  have 
them  in  one  or  more  clusters,  some  in  rows,  and  others  scat- 
tered about.  They  appear  to  be  able  to  see  as  well  by  night  as 
by  day.  Near  the  end  of  the  body  are  the  spinnerets — two, 
three,  or  four  pairs — out  of  which  the  silk  comes  for  weaving 
the  webs,  nests,  and  egg  cocoons. 

Usually  the  female  spider  is  much  larger  and  stronger  than 
the  male.  One  naturalist  thus  graphically  describes  their 
wedded  life :  "  Their  honeymoon  is  of  short  duration,  and  is 
terminated  by  the  bride's  banqueting  on  the  bridegroom. 
Doubtless  she  evinces  taste  and  discrimination  in  her  apprecia- 
tion of  a  'nice  young  man.'  " 

Spiders,  like  lobsters  and  other  crustaceans,  have  the  power 
of  reproducing  certain  parts  if  they  happen  to  meet  with  an  in- 
jury, as  legs,  palpi,  and  spinnerets. 


EVOLUTION  AND  NATUEE  STUDIES          375 

We  find  as  marked  differences  in  habits,  tastes,  and  char- 
acters among  spiders  as  among  human  beings.  Some  kinds 
prefer  always  living  in  houses  or  cellars,  not  seeming  to  care 
for  any  fresh  air  or  out-of-door  exercise.  Mr.  Jesse  tells  of  two 
spiders  that  lived  for  thirteen  years  in  opposite  corners  of  a 
drawer  which  was  used  for  soap  and  candles.  Others  delight 
in  making  burrows  in  the  earth,  in  dwelling  under  stones  or 
behind  the  loose  bark  on  trees,  and  others  live  under  water. 
Many  never  leave  their  webs,  but  patiently  wait,  hoping  some 
insect  will  become  entangled  in  the  snares  they  have  set. 
Others  dash  about  and  seize  upon  every  luckless  insect  that 
crosses  their  path.  The  most  adventurous  of  all  are  those  that 
sail  out  into  the  world  on  one  of  their  own  little  threads.  Dar- 
win tells  of  encountering  thousands  of  them  many  leagues  from 
land  when  he  was  taking  his  famous  voyage  in  the  "  Beagle." 
He  says :  "  The  little  aeronaut,  as  soon  as  it  arrived  on  board, 
was  very  active,  running  about,  sometimes  letting  itself  fall, 
then  reascending  the  same  thread.  It  could  run  with  facility  on 
the  surface  of  the  water." 

In  the  bright  autumn  weather,  if  we  observe  closely,  we 
may  sometimes  see  some  of  our  own  small  spiders  ascend  to 
the  tops  of  trees,  fences,  and  other  high  objects,  rise  on  their 
toes,  turn  the  spinners  upward,  throw  out  a  quantity  of  silk, 
and  sail  away.  They  can  be  seen  plentifully  any  fine  day  in 
October  or  November,  before  the  cold  weather,  on  Boston 
Common.  They  grasp  the  silken  thread  with  their  feet  and 
seem  to  be  enjoying  themselves  as  much  as  the  birds  and 
butterflies. 

Many  instances  are  recorded  of  music-loving  spiders,  per- 
haps the  most  interesting  being  that  related  by  Beethoven's 
biographer,  who  says :  "  A  spider  weaving  its  skillful,  though 
delicate,  trap  for  its  daily  dinner  worked  industriously  in  the 
corner  of  the  ceiling  until  Beethoven  began  to  play.  Beethoven, 
who  at  that  time  had  not  thousands  hanging  on  his  baton,  was 
rather  pleased  and  attached  to  this  listener,  which  most  practi- 
cally proved  the  value  it  attached  to  the  performance  by  risking 
its  life  in  coming  nearer  the  enchanted  instrument.  And  ill 
was  it  rewarded.  The  mother  one  day,  perceiving  the  ugly 


376  ACHIEVEMENTS  IN  SCIENCE 

animal,  seized  and  killed  it.  But  the  boy  Beethoven  was  so 
put  out  and  so  miserable  at  losing  his  strange  auditor  that  he 
burst  into  tears  and,  seizing  his  violin,  smashed  it  against  the 
floor,  shivering  it  into  a  thousand  pieces." 

Many  kinds  build  their  webs  and  cocoons  in  exposed  places 
and  take  no  pains  to  conceal  them,  while  others  cover  theirs 
with  tiny  pebbles  and  bits  of  earth  for  protection.  Some  kinds 
of  spiders  abandon  their  egg  cocoon  as  soon  as  it  is  finished, 
while  others  carry  it  about  with  them  until  the  babies  appear. 
One  mother  allowed  herself  to  be  torn  to  pieces  rather  than 
leave  her  cocoon. 

We  might  compare  the  spider's  different  modes  of  getting 
about  to  those  of  the  birds.  The  hunting  spiders  leap  and  hop, 
the  house  spiders  generally  run  forward,  other  kinds  run  back- 
ward and  sideways  with  equal  facility,  and  some,  as  we  have 
seen,  float  about  in  the  air.  The  most  marvelous  of  the  spi- 
ders' gifts  is  the  silk-spinning.  The  spinnerets  or  spinners  are 
little  organs  at  the  hind  end  of  the  body.  Each  has  a  number 
of  very  minute  holes  in  it.  Out  of  these  the  silk  flows  in  a 
liquid  form,  but  as  soon  as  the  air  strikes  it  it  hardens  into  a 
thread.  The  strands  from  the  different  holes  all  unite  and 
form  what  we  know  as  the  spider's  thread.  There  are  great 
differences  in  the  kinds  of  webs  and  nests  which  different  spi- 
ders make.  One  of  the  most  interesting  is  the  web  of  the 
great  black-and-gold  garden  spider.  First  she  spins  several 
lines  all  joined  in  the  center  like  the  spokes  of  a  wheel,  and  at- 
tached to  stems  or  leaves  of  plants  at  the  outer  edges.  When 
the  rays  are  finished  she  begins  at  the  middle  to  make  the 
spiral  part.  It  is  fascinating  to  watch  her,  as  she  crosses  each 
spoke,  stop  and  pat  down  the  silk  once  or  twice,  then  pull  it  to 
see  if  it  is  well  secured  before  passing  to  the  next  one.  When 
the  web  is  finished,  she  makes  a  zigzag  ladder  of  white  silk, 
running  from  the  bottom  outer  edge  to  the  center.  When  she 
hangs  in  the  middle  of  her  web,  as  she  does  much  of  the  time, 
the  ladder  helps  to  conceal  her.  The  web  is  made  of  two  kinds 
of  silk — one  smooth,  the  other  covered  with  an  adhesive  liquid. 
When  the  insects  are  caught,  their  legs  and  wings  are  soon 
covered  with  the  sticky  juice,  so  that  it  is  impossible  for  them 


I 


EVOLUTION  AND  NATURE  STUDIES          377 

to  escape.  The  spider,  knowing  it  would  not  be  convenient  to 
become  entangled  herself,  spins  one  long,  smooth  thread  from 
the  center  to  the  outside,  which  she  uses  in  traveling  to  and  fro. 

The  common  house  spider  is  wonderfully  sagacious.  Once 
in  a  while  a  large  insect  is  caught  in  her  web.  She  wants  to 
take  it  up  to  her  inner  retreat  to  devour,  and  it  is  too  heavy  for 
her  to  carry.  What  is  she  to  do  ?  First  she  bites  its  leg,  in- 
jecting some  of  her  poison,  which  stupefies  it.  Next  she 
throws  some  additional  threads  about  it  and  ascends  to  the  top, 
pulling  the  thread  as  hard  as  she  can.  When  she  has  rested 
for  a  little  time,  she  winds  more  threads  about  her  victim  and 
pulls  again,  each  time  attaching  the  threads  at  the  top.  In  this 
way  she  finally  succeeds  in  hoisting  her  feast  into  her  house, 
though  the  process  may  last  several  days. 

Who  would  think  that  our  predecessors  in  the  art  of  curling 
the  hair  were  spiders  ?  One  species  has  been  provided  by  Na- 
ture with  a  sort  of  little  curling  comb  called  the  calimistra.  It 
is  on  the  hind  legs  and  consists  of  two  rows  of  parallel  spines. 
The  web,  which  she  makes  of  bluish-white  silk,  is  unusually 
pretty,  as  each  thread  is  gracefully  curled  by  drawing  it  be- 
tween the  spines. 

Thoreau  calls  the  little  gossamer  webs  which  we  see  spread 
over  the  grass  on  a  dewy  morning  the  napkins  of  the  fairies. 
Even  Chaucer,  who  wrote  five  hundred  years  ago,  mentions 
them  as  a  great  curiosity  to  the  people  of  his  time.  He  says : 

As  sore  wondren  som  on  cause  of  thonder, 
On  ebb  and  flood,  on  gossamer  and  on  mist, 
And  on  all  thing,  'til  that  the  cause  is  wist. 

A  hundred  and  fifty  years  ago  a  Frenchman,  M.  Le  Bon, 
made  some  stockings,  purses,  and  gloves  from  spiders'  silk. 
The  Bermuda  ladies  use  the  thread  of  Nephila  for  sewing,  and 
Queen  Victoria  was  presented  by  the  Empress  of  Brazil  with  a 
dress  made  of  spiders'  silk. 

Spiders  molt  several  times,  each  time  appearing  in  a  differ- 
ent color.  We  should  hardly  expect  to  find  very  brilliant  or 
showy  colors  among  them,  yet  some  of  them  are  gorgeous  in 
the  extreme.  A  little  crab  spider  that  built  a  house  in  my  gar- 


378  ACHIEVEMENTS  IN  SCIENCE 

den  was  the  brightest  lemon-yellow  all  over,  and  shone  like  a 
jewel  amid  the  dark  green  of  the  surrounding  foliage. 

One  of  the  English  spiders  has  a  black  head  and  thorax, 
with  an  orange-red  body,  on  which  are  six  black  spots,  each 
ringed  with  white ;  another  has  a  green  coat  with  brilliant  red 
and  yellow  striped  trousers,  for  all  the  world  like  a  king's  jester. 
One  dainty  lady  is  clad  in  violet  and  white,  a  flaunting  miss  in 
black  and  flame-color,  and  her  sister  in  cherry  and  brown. 

Some  of  the  Thomisidce  are  the  exact  colors  of  certain 
flowers,  in  the  centers  of  which  they  sit  all  day,  watching  for 
the  insects  that  come  to  get  honey. 

Two  of  the  spiders'  worst  enemies  are  mud  wasps  and 
ichneumon  flies.  In  searching  recently  for  spiders  beneath  the 
clapboards  on  the  south  side  of  the  house,  I  came  across  one  of 
those  curious  structures  which  the  mud  wasp  builds.  I  broke 
it  open,  and  out  tumbled  a  quantity  of  small  spiders.  The 
wasp's  storehouse  was  in  three  compartments,  and  all  together 
contained  forty-nine  spiders,  all  of  the  same  kind  and  about  the 
same  size,  in  a  torpid  condition.  The  wasp  had  laid  an  egg  in 
each  of  these  spiders.  She  does  not  kill  the  spider,  but  merely 
stupefies  it,  so  that  when  her  egg  hatches  the  larva  may  feed 
upon  the  luckless  spider. 

If  one  be  a  student  of  Nature  he  will  perhaps  have  noticed 
a  spider  rush  away  and  hide  in  her  crack  without  any  apparent 
reason.  The  moment  before  she  had  been  enjoying  the  bright 
sunshine,  and  the  student  wonders  why  she  ran  away.  The 
spider's  perceptions  are  so  keen  that  she  knows  long  before  he 
does  that  the  sky  will  soon  be  overcast  and  torrents  of  rain  de- 
scend or  a  cold  wind  begin  to  blow.  If  she  stayed  out  she 
might  soon  be  benumbed  and  unable  to  run  into  her  house. 

The  water  spiders  are  covered  with  hairs  which  shed  the 
water,  so  that  they  never  get  wet.  The  little  house  under  the 
water  in  which  they  live  and  raise  their  families  is  as  snug  and 
dry  inside  as  yours  and  mine. 

No  spiders  are  more  interesting  than  the  trapdoor  spiders 
and  their  first  cousins  the  tarantulas.  The  former  live  in 
Europe  and  California.  First,  they  make  a  burrow  in  the 
ground  and  then  build  the  door.  The  California  ones  make 


EVOLUTION  AND  NATURE  STUDIES         379 

their  door  of  mud  and  sticks.  It  fits  into  the  tube  as  a  cork 
does  into  a  bottle.  The  covers  built  by  the  European  species 
are  mere  little  lids,  but  they  are  always  built  so  as  to  resemble 
the  surrounding  surface.  One  kind  shows  her  sagacity  by 
building  a  sort  of  double  door,  by  which  she  can  escape  should 
an  enemy  storm  her  fort.  At  the  surface  is  the  usual  door, 
and  a  few  inches  below  this  another.  When  the  spider  hears 
an  enemy  investigating  her  burrow,  she  runs  below  the  second 
door  and  pushes  it  up,  so  that  the  marauder  will  think  he  has 
happened  upon  a  empty  nest,  the  second  door  forming  the  bot- 
tom of  it.  The  babies  are  born  in  the  tubes,  and  remain  with 
their  mother  until  they  are  able  to  make  nests  for  themselves. 

These  spiders  spend  the  days  in  their  burrows,  but  at  night 
they  all  flock  out  to  enjoy  themselves.  They  fasten  open  their 
doors  and  make  little  webs  over  the  grass.  Many  night-wan- 
dering beetles  are  caught,  and  then  comes  the  banquet,  which 
consists  of  the  softer  parts  of  the  beetles.  In  the  morning  the 
closest  observer  could  not  find  a  trace  of  the  preceding  night's 
revelry,  so  carefully  have  the  spiders  cleared  away  all  webs, 
beetle  legs,  and  wing  covers. 

One  group  of  spiders  is  called  Lycosa,  which  means  wolf 
spider.  Perhaps  they  were  named  from  the  similarity  of  their 
habits  to  those  of  the  wolf,  being  like  him  wandering  and  pre- 
daceous. 

One  of  these  is  the  tarantula,  a  great  hairy  fellow  who  in- 
habits warm  countries.  The  species  received  its  name  from 
the  Italian  city  of  Tarentum,  where  they  have  been  found  in 
large  numbers.  There  is  a  curious  superstition  connected  with 
the  tarantula's  bite.  If  a  person  was  bitten  it  was  thought 
nothing  could  save  his  life  but  the  playing  of  some  lively  danc- 
ing tunes.  When  he  heard  these  he  was  supposed  to  be  unable 
to  resist  the  temptation  to  dance.  Thus  he  grew  very  warm, 
and  the  perspiration  came  out  in  great  beads  all  over  him,  each 
bead  filled  with  poison.  After  he  had  danced  as  long  as  he 
possibly  could,  the  poison  had  all  escaped  from  his  system. 
The  tarantulas  feed  on  small  birds  as  well  as  insects.  Indeed, 
one  of  the  great  southern  species  is  called  the  bird-catching 
spider. 


380  ACHIEVEMENTS  IN  SCIENCE 

In  India,  where  all  animals  are  treated  with  consideration 
and  even  reverence,  the  little  children  often  keep  these  spiders 
for  pets.  They  tie  a  cord  round  a  spider  and  lead  it  about, 
feeding  it  with  worms  and  insects.  Mother  Lycosa  always  car- 
ries her  egg  cocoons  out  with  her  on  her  hunting  expeditions, 
attached  to  the  spinnerets. 

One  summer  I  kept  a  garden  spider  for  three  weeks  under 
a  tumbler,  and  had  the  pleasure  of  watching  her  building  her 
house  of  snowy  silk,  with  its  three  entrances,  and  raising  a  large 
family  of  children.  She  soon  learned  to  take  flies  from  my 
hand  and  drink  water  from  a  leaf  which  I  gave  her  fresh  every 
day.  After  a  time  she  seemed  to  languish  and  droop,  so  I  set 
her  free  in  the  garden  once  more. 

If  you  wish  to  live  and  thrive, 
Let  a  spider  run  alive. 

says  the  old  Kentish  proverb. 


EVOLUTION  AND  NATURE  STUDIES 


The  Nocturnal  Migration  of  Birds 

By  FRANK  M.   CHAPMAN 

NO  branch  of  ornithology  offers  more  attractions  to  the  stu- 
dent of  birds  than  the  fascinating  subject  of  migration. 
Birds  come  and  go ;  absent  to-day,  to-morrow  they  greet  us 
from  every  tree  and  hedgerow.  Their  departure  and  arrival 
are  governed  by  as  yet  unknown  laws ;  their  journeys  though 
the  pathless  sky  are  directed  by  an  instinct  or  reason  which 
enables  them  to  travel  thousands  of  miles  to  a  winter  home, 
and  in  the  spring  to  return  to  the  nest  of  the  preceding  year. 
Volumes  have  been  written  to  explain  their  mysterious  appear- 
ances and  disappearances. 

Theories  almost  as  numerous  as  the  essays  themselves  have 
been  advanced  to  account  for  the  phenomena  of  migration. 
From  the  time  of  Jeremiah  (viii.  7)  to  the  present  day  we 
might  cite  a  host  of  authors  who  have  contributed  to  the  litera- 
ture of  the  subject.  It  is  not  our  intention,  however,  to  review 
the  whole  question  of  migration.  The  combined  researches  of 
ornithologists  have  placed  it  among  the  sciences,  and  its  more 
prominent  facts  are  common  knowledge.  We  desire  here  to  call 
attention  to  but  one  phase  of  the  study,  and  more  especially  to 
outline  some  recent  investigations  in  connection  with  the  noc- 
turnal migrations  of  birds. 

From  the  nature  of  the  case,  our  data  concerning  these 
night  flights  have  long  been  meager  and  unsatisfactory.  Even 
now  our  information  has  but  reached  a  stage  which  permits  us 
to  intelligently  direct  further  effort. 

We  know  that  the  land  birds  which  migrate  by  night  in- 

381 


382  ACHIEVEMENTS  IN  SCIENCE 

elude  species  of  more  or  less  retiring  disposition,  whose  com- 
paratively limited  powers  of  flight  would  render  them  easy  vic- 
tims for  birds  of  prey  if  they  ventured  far  from  the  protection 
of  their  natural  haunts  during  the  day.  Thus  we  find  that  the 
bush-  or  tree-loving  thrushes,  wrens,  warblers,  and  vireos  all 
choose  the  night  as  the  most  advantageous  time  in  which  to 
make  their  long  semi-annual  pilgrimage,  while  such  bold  rovers 
as  swallows,  swifts,  and  hawks  migrate  exclusively  by  day. 

The  information  we  possess  concerning  the  manner  in  which 
the  first-mentioned  class  of  birds  accomplish  a  journey  which 
leads  them  from  boreal  regions  to  the  tropics,  has  been  derived 
from  three  sources :  First,  through  the  birds  which  are  killed 
by  striking  lighthouses  or  electric-light  towers ;  second,  through 
observations  made  at  night  from  similar  structures ;  and,  third, 
through  the  use  of  the  telescope. 

It  has  long  been  known  that  lighthouses  are  most  destruc- 
tive to  night-migrating  birds.  Probably  no  one  artificial  cause 
produces  more  disastrous  results  than  these  beacons  which 
guide  the  mariner  in  safety,  but  prove  fatal  obstacles  in  the 
path  of  aerial  voyagers. 

The  number  of  birds  killed  by  striking  lighthouses  is  incal- 
culable. Over  fifteen  hundred  have  been  found  dead  at  the 
foot  of  the  Bartholdi  statue  in  a  single  morning ;  while  from 
Fire  Island  (Long  Island)  light  we  have  a  record  of  two  hun- 
dred and  thirty  birds  of  one  species — black-poll  warblers  which 
met  their  fate  on  the  night  of  September  30,  1883. 

Reports  from  numerous  lighthouses  show  (i)  a  great  varia- 
tion in  avian  mortality  at  different  localities;  (2)  that  as  a  rule 
no  birds  are  killed  during  clear  nights;  and  (3)  that  compara- 
tively few  birds  strike  the  lights  during  the  vernal  migration. 
The  fact  that  birds  follow  certain  routes  or  highways  of  migra- 
tion in  their  journeys  to  and  from  the  South  doubtless  explains 
their  absence  or  presence  at  a  given  locality;  indeed,  it  has 
been  definitely  ascertained  that  lights  which  are  situated  in 
known  lines  of  migration — as  for  example,  the  Bartholdi  statue 
at  the  mouth  of  the  Hudson  River  valley — prove  far  more  de- 
structive than  those  which  are  placed  far  from  the  regular 
routes  of  migrating  birds. 


EVOLUTION  AND  NATURE  STUDIES          383 

Through  telescopic  observations,  to  be  mentioned  later,  we 
have  learned  that  when  en  route  birds  travel  at  an  altitude  of 
from  one  to  three  miles  above  the  earth.  It  is  obvious,  then, 
that  when  their  way  is  not  obscured  by  low-hanging  clouds 
they  pass  too  far  above  us  to  be  attracted  by  terrestrial  objects. 
It  has  been  noted  that  cloudy  and  especially  rainy  nights  are 
most  disastrous  to  migrants,  evidently  because  the  formation 
of  moisture  at  the  elevation  at  which  they  are  flying  must  not 
only  interfere  with  their  progress,  but,  also  because,  in  veiling 
the  earth  below,  it  robs  them  of  their  landmarks,  while  the  con- 
densation of  this  moisture  into  rain  presents  an  effectual  check 
to  flight.  The  birds  then  descend  to  a  lower  altitude,  and, 
should  the  storm  be  very  severe,  they  are  obliged  to  seek  the 
nearest  shelter,  and  may  even  be  driven  to  earth  wet,  helpless, 
and  dying. 

The  influence  thus  shown  to  be  exerted  by  meteorological 
conditions  is  the  best  explanation  of  the  comparatively  small 
number  of  birds  killed  during  the  spring  migration,  when  the 
infrequency  of  violent  storms  enables  them  to  perform  their 
journey  with  less  danger  from  exposure  to  the  elements. 

The  observations  of  Mr.  William  Brewster  on  the  migration 
of  birds  at  the  Point  Lepreaux  (Bay  of  Fundy)  lighthouse  have 
never  been  exceeded  in  interest  or  value  by  the  recorded  expe- 
riences of  any  other  observer  of  similar  phenomena.  Still, 
even  his  graphic  account  fails  to  produce  the  sensations  which 
possess  one  when  for  the  first  time  the  air  at  night  is  actually 
seen  to  be  filled  with  the  tiny  songsters  which  before  were 
known  only  as  timid  haunters  of  woods  and  thickets. 

On  September  26,  1891,  it  was  the  writer's  good  fortune  to 
pass  the  night  with  several  ornithologists  at  the  Bartholdi 
statue  in  observing  the  nocturnal  flight  of  birds.  The  weather 
was  most  favorable  for  our  purpose.  From  the  balcony  at  the 
base  of  the  statue  we  saw  the  first  bird  enter  the  rays  of  light 
thrown  out  by  the  torch,  one  hundred  and  fifty  feet  above  us,  at 
eight  o'clock.  During  the  two  succeeding  hours  birds  were 
constantly  heard  and  many  were  seen.  At  ten  o'clock  a  light 
tin  began  to  fall  and  for  three  hours  it  rained  intermittently. 
Imost  simultaneously  there  occurred  a  marked  increase  in 


384  ACHIEVEMENTS  IN  SCIENCE 

the  number  of  birds  seen  about  the  light,  and  within  a  few 
minutes  there  were  hundreds  where  before  there  was  one, 
while  the  air  was  filled  with  the  calls  and  chirps  of  the  passing 
host. 

The  birds  presented  a  singular  appearance.  As  they 
entered  the  limits  of  the  divergent  rays  of  light  they  became 
slightly  luminous,  but  as  their  rapid  wing-beats  brought  them 
into  the  glare  of  the  torch  they  reflected  the  full  splendor  of 
the  light,  and  resembled  enormous  fireflies  or  swarms  of  huge 
golden  bees. 

At  eleven  o'clock  we  climbed  to  the  torch  and  continued 
our  observations  from  the  balcony  by  which,  it  is  encircled. 
The  scene  was  impressive  beyond  description ;  we  seemed  to 
have  torn  aside  the  veil  which  shrouds  the  mysteries  of  the 
night,  and  in  the  searching  light  reposed  the  secrets  of  Nature. 
As  the  tiny  feathered  wanderers  emerged  from  the  surround- 
ing blackness,  appeared  for  a  moment  in  the  brilliant  halo 
about  us,  and  continuing  their  journey  were  swallowed  up  in 
the  gloom  beyond,  one  marveled  at  the  power  which  guided 
them  thousands  of  miles  through  the  trackless  heavens.  While 
by  far  the  larger  number  hurried  onward  without  pausing  to 
inspect  this  strange  apparition,  others  hovered  before  us  like 
humming-birds  before  a  flower,  then  wheeling,  retreated  for  a 
short  distance  and  returned  to  repeat  the  performance  or  pass 
us  as  did  the  first  class  mentioned,  while  others  still,  and  the 
number  was  comparatively  insignificant,  struck  some  part  of 
the  torch  either  slightly  or  with  sufficient  force  to  cause  them 
to  fall  stunned  or  dying.  It  was  evidently  by  the  merest  acci- 
dent that  they  struck  at  all;  and,  so  far  as  we  could  judge,  they 
were  either  dazzled  by  the  rays  of  the  light  and  thus  unwit- 
tingly flew  directly  at  the  glass  which  protects  it,  or  came  in 
contact  with  some  unilluminated  part  of  the  statue.  During 
the  two  hours  we  were  in  the  torch  thousands  of  birds  passed 
within  sight,  but  less  than  twenty  were  killed. 

This  fact,  in  connection  with  the  comparative  or  entire  ab- 
sence of  birds  on  clear  nights,  very  plainly  shows  that  conclu- 
sions based  solely  on  these  casualties  may  be  not  only  mislead- 
ing but  also  erroneous.  In  other  words,  the  number  of  birds 


EVOLUTION  AND  NATURE  STUDIES          385 

which  strike  a  light  is  a  poor  index  to  the  number  which  have 
flown  by  or  above  it  in  safety. 

Throughout  the  evening  there  was  a  more  or  less  regular 
fluctuation  in  the  number  of  birds  present ;  periods  of  abun- 
dance were  followed  by  periods  of  scarcity,  and  the  birds  passed 
in  well-defined  flights,  or  loose  companies,  probably  composed  in 
the  main  of  individuals  which  had  started  together. 

The  birds  chirped  and  called  incessantly.  Frequently, 
when  few  could  be  seen,  hundreds  were  heard  passing  in  the 
darkness ;  the  air  was  filled  with  the  lisping  notes  of  warblers 
and  the  mellow  whistle  of  thrushes,  and  at  no  time  during  the 
night  was  there  perfect  silence.  At  daybreak  a  few  stragglers 
were  still  winging  their  way  southward,  but  before  the  sun  rose 
the  flights  had  ceased.  The  only  birds  identified  were  several 
species  of  warblers  and  thrushes,  one  red-eyed  vireo,  two  golden- 
winged  woodpeckers,  one  catbird,  one  whip-poor-will,  and  one 
bobolink.  The  most  interesting  and  important  results  of  the 
night's  observations  were  the  immediate  effect  of  rainfall  in 
forcing  birds  to  migrate  at  a  lower  level,  the  infrequency  with 
which  they  struck  the  torch,  the  immense  number  which  passed 
beyond  its  rays,  and  the  constancy  with  which  they  called  and 
chirped  as  they  flew. 

An  almost  virgin  field  awaits  the  investigator  who  will  sys- 
tematically observe  night-migrating  birds  with  the  aid  of  a  tele- 
scope. Messrs.  Allen  and  Scott,  at  Princeton,  and  the  writer, 
assisted  by  Mr.  John  Tatlock,  Jr.,  at  Tenafly,  New  Jersey, 
and  at  the  Columbia  College  Observatory,  have  alone  recorded 
the  results  of  observations  of  this  nature.  Their  labors,  how- 
ever, were  too  brief  to  show  more  than  the  possibilities  which 
await  more  extended  effort. 

A  comparatively  low-power  glass  is  focused  upon  the  moon, 
the  birds  appearing  silhouetted  upon  its  glowing  surface  as 
they  cross  the  line  of  vision.  Some  idea  of  the  multitude  of 
feathered  forms  which  people  the  upper  regions  of  the  air  at 
night  may  be  formed  when  it  is  stated  that  during  three  hours' 
observation  at  Tenafly  no  less  than  two  hundred  and  sixty-four 
birds  were  seen  crossing  the  restricted  field  included  in  the 
angle  subtended  by  the  full  moon.  Under  proper  focal  condi- 
25 


386  ACHIEVEMENTS  IN  SCIENCE 

tions,  birds  were  so  plainly  visible  that  in  many  instances 
marked  character  of  flight  or  form  rendered  it  possible  to  recog- 
nize the  species.  Thus  ducks,  snipe,  and  sora  rail  were  distin- 
guished with  certainty. 

The  effect  on  the  observer  of  this  seeing  of  things  unseen 
is  not  a  little  curious,  and  may  be  likened  to  the  startling  dis- 
closures which  a  high-power  microscope  presents  in  a  drop  of 
water. 

From  calculations  based  on  an  assumption  that  birds  were 
not  visible  beyond  a  distance  of  five  miles,  we  determined  the 
greatest  altitude  at  which  birds  migrate  to  be  three  miles  above 
the  earth's  surface.  Many,  however,  fly  at  a  lower  level ;  in- 
deed, it  is  not  improbable  that  certain  species  may,  with  more 
or  less  regularity,  travel  at  a  given  altitude,  and  that  this  alti- 
tude may  vary  among  birds  of  different  families.  With  little 
doubt  thrushes  and  warblers  travel  at  a  much  lower  level  than 
do  ducks  and  geese,  a  circumstance  which  may  account  for  the 
great  abundance  of  the  first  two  named  and  the  comparative 
absence  of  the  last  in  the  vicinity  of  lighthouses. 

Such,  in  brief,  are  the  sources  and  methods  to  which  we 
owe  our  knowledge  of  the  nocturnal  flight  of  birds.  It  will  be 
evident  to  the  most  casual  reader  how  incomplete  are  our  data. 
The  time  is  still  far  distant  when  we  can  hope  to  account  con- 
clusively for  the  many  perplexing  phenomena  of  migration,  but 
we  may  be  pardoned  if,  in  conclusion,  we  briefly  review  the 
bearing  of  our  present  information. 

We  need  not  discuss  here  the  origin  of  migration  or  the 
causes  which  now  induce  birds  to  undertake  a  long  and  perilous 
journey  twice  each  year.  But  the  power  and  influences  which 
guide  a  bird,  in  the  darkness  of  the  night,  through  space,  and 
render  a  definite  migration  possible,  are  subjects  kindred  to  our 
inquiry  and  worthy  our  attention. 

Until  we  possess  some  exact  knowledge  of  the  distance  to 
which  birds  can  see  we  cannot  estimate  the  aid  their  vision  is 
to  them  while  migrating.  We  know,  however,  that  the  avian 
eye  is  far  more  powerful  than  ours,  and  it  is  fair  to  assume  that 
to  some  extent  their  journeys  are  directed  by  a  sight  which 
enables  them  to  follow  mountain  chains,  river  valleys,  and 


EVOLUTION  AND  NATURE  STUDIES          387 

coast  lines,  and  to  distinguish  distant  headlands  or  islands.  At 
an  altitude  of  two  miles  an  object  would  be  visible  ninety  miles 
and  the  horizon  be  separated  by  twice  this  distance.  At  no 
time,  therefore,  in  their  journey  from  North  to  South  America 
are  birds  necessarily  out  of  sight  of  land.  But  that  they  do 
venture  beyond  a  point  where  land  is  visible  is  shown  by  the 
regular  appearance  of  migrants  in  the  Bermudas,  six  hundred 
miles  from  our  coast,  while  Jamaica,  four  hundred  miles  north 
of  the  nearest  point  of  South  America,  is  a  point  of  departure 
for  many  south-bound  migrants.  Here,  with  neither  islet, 
shoal,  nor  reef  to  mark  the  way,  it  is  evident  that  sight  alone 
would  prove  an  insufficient  guide,  and  they  must  rely  on  some 
other  sense.  Primarily,  this  is  the  inherited  habit  which 
prompts  birds  to  fly  southward  in  the  fall  and  to  return  in  the 
spring.  But,  given  the  impulse  of  direction,  there  is  little 
doubt  that  one  of  the  best  guides  to  night-flying  birds  is  the 
sense  of  hearing.  Birds'  ears  are  exceedingly  acute.  They 
readily  detect  sounds  which  to  us  are  inaudible.  Almost  inva- 
riably they  will  respond  to  an  imitation  of  their  notes.  We 
have  seen  that  when  under  way  they  constantly  chirp  and  call, 
and  when  we  take  into  consideration  their  aural  power  and  their 
abundance  in  highways  of  migration,  it  is  probably  that  at  no 
time  during  the  night  is  a  bird  out  of  hearing  of  its  fellow- 
travelers.  The  line  of  flight  once  established,  therefore,  pre- 
sumably by  the  older  and  more  experienced  birds,  it  becomes  a 
comparatively  easy  matter  for  the  novice  to  join  the  throng. 


EVOLUTION  AND  NATURE  STUDIES 


Wingless  Birds 

By  PHILIPPE  GLANGEAUD 

IT  is  often  said  that  there  are  no  rules  without  exceptions. 
We  purpose  to  test  the  truth  of  this  maxim  once  more. 
Fishes  are  made  to  live  in  water,  but  some  of  them  pass  the 
greater  part  of  their  existence  in  mud.  Some  even  perch  upon 
trees,  thus  competing  with  birds,  whose  kingdom  is  the  air, 
and  which  are  able,  with  the  aid  of  their  wings,  to  plunge  into 
space  and  travel  rapidly  over  considerable  distances.  Yet 
there  are  birds,  deprived  by  Nature,  which  do  not  possess  the 
wing  characteristic  of  the  feathered  tribe,  and  are,  consequently, 
like  the  majority  of  animals,  pinned  to  the  soil. 

Birds  do  not  all  have  equal  power  of  flight,  which  is  closely 
related  to  the  extent  of  the  development  of  their  wings.  There 
exist  all  grades  in  the  spread  of  wings,  between  that  of  the  con- 
dor, which  is  four  times  the  length  of  the  body,  whereby  the 
bird  is  able  to  rise  to  the  height  of  nearly  twenty-five  thousand 
feet,  and  the  little  winglets  of  the  auk,  which  are  of  no  use  to 
it.  The  penguins  have  still  smaller  wings,  which  are  nothing 
more  than  short,  flattened  stumps,  without  proper  feathers  and 
covered  with  a  fine,  hairlike  down  which  might  be  taken  for 
scales. 

Another  group  of  birds  exists,  called  appropriately  Brevi- 
pennes,  the  wings  of  which  are  so  poorly  developed  as  to  be 
wholly  unsuitable  for  flight.  As  an  offset  and  just  compensa- 
tion for  this,  their  long  and  robust  legs  permit  them  to  run 
with  extraordinary  speed.  For  that  reason  they  have  been 
called  running  birds,  in  distinction  from  other  kinds  that  con- 

388 


EVOLUTION  AND  NATURE  STUDIES          389 

stitute  the  group  of  flying  birds.  Among  them  are  some  gigan- 
tic birds,  and  also  some  that  have  no  visible  wings  on  the  out- 
side of  their  bodies,  and  may  therefore  be  properly  called 
wingless. 

The  ostrich  is  a  member  of  this  group.  With  its  bare,  cal- 
lous head  and  short  bill,  its  long,  featherless  neck,  and  its  mas- 
sive body,  supported  by  long,  half-bare  legs,  ending  in  two 
large  toes ;  its  very  short  wings,  formed  of  soft  and  flexible 
feathers ;  and  its  plume-shaped  tail,  it  presents  a  very  special 
appearance  among  the  birds. 

The  nandous,  the  American  representatives  of  the  ostrich, 
have  still  shorter  wings,  which  have  no  remigia  at  all,  and  ter- 
minate in  a  horny  appendage;  they  have  no  tail  feathers. 

The  cassowary  and  the  emu  also  resemble  the  ostrich  in 
many  points,  but  their  wings  are  still  more  reduced  than  those 
of  the  nandou.  They  are  only  slightly  distinct,  and  cannot  be 
seen  when  the  bird  holds  them  close  to  its  body.  In  the 
Apteryx,  the  name  of  which,  from  the  Greek,  means  without 
wings,  the  organs  of  flight  are  hardly  apparent,  and  consist 
simply  of  a  very  short  stump  bearing  a  thick  and  hooked  nail. 
The  Apteryx,  which  is  also  called  Kiwi,  a  native  of  New  Zea- 
land, is  the  most  singular  of  living  birds.  The  neck  and  the 
body  are  continuous,  and  the  moderately  sized  head  is  furnished 
with  a  long  beak  resembling  that  of  the  ibis.  Having  long 
hairs  similar  to  the  mustaches  of  cats  at  its  base,  it  is  different 
from  the  bills  of  all  other  existing  birds  in  possessing  nostrils 
that  open  at  its  upper  point.  Although  the  Apteryx  cannot  fly, 
it  runs  very  fast,  despite  the  shortness  of  its  legs,  and  can  de- 
fend itself  very  effectively  against  assailants  by  the  aid  of  its 
long-nailed  and  sharp-nailed  feet.  The  tail  is  absent  like  the 
wings.  The  very  pliant  feathers  are  extremely  curious,  of  the 
shape  of  a  lance-head,  pendant,  loose,  silky,  with  jagged  barbs, 
and  increase  in  length  as  they  go  back  from  the  neck.  The 
bird  is  of  the  size  of  a  fowl,  and  when  in  its  normal  position 
stands  with  its  body  almost  vertical,  and  carries  the  suggestion 
of  a  caricature — resembling,  we  might  say,  a  feathered  sack, 
with  only  a  long-billed  head  and  the  claws  projecting,  so  that 
one  beholding  it  feels  that  he  is  looking  at  some  unfinished  crea- 


390  ACHIEVEMENTS  IN  SCIENCE 

ture.  It  is  a  nocturnal  bird,  of  fierce  temper,  and  has  become 
rare  in  consequence  of  the  merciless  war  that  is  made  upon  it. 
Everything  is  strange  about  it,  even  the  single  egg  it  lays, 
which  weighs  about  a  quarter  as  much  as  its  body. 

Together  with  the  Apteryx  there  lived,  in  New  Zealand  a 
bird  that  reached  the  height  of  nearly  twelve  feet — the  Dinor- 
nis.  It  and  the  Phororhaces  and  the  Brontornis,  which  have 
been  recently  exhumed  in  Patagonia,  might  be  regarded  as  the 
giants  of  birds.  This  bird  was  known  to  the  natives  as  the 
Moa,  and  lived  in  troops  like  the  ostriches.  Its  organization 
was  very  much  like  that  of  the  Apteryx,  from  which  it  was  dis- 
tinguished, however,  by  its  great  size,  long  neck,  and  short  beak. 
It  seems  to  have  had  the  aspect  of  an  ostrich,  with  a  feathered 
neck  and  no  wings  or  tail.  The  feet  of  the  Dinornis,  with  their 
three  large  toes,  were  really  enormous.  Isolated  fragments  of 
its  bones  suggest  very  large  mammals,  rather  than  birds. 
The  femur  and  tibia  are  larger  than  those  of  a  bear,  the  tibia 
alone  being  about  four  feet  long,  and  the  thickness,  in  the  nar- 
rowest part,  of  the  width  of  a  man's  hand,  while  it  was  more 
than  seven  inches  in  the  thickest  part.  The  sternum,  on  the 
other  hand,  was  small,  convex,  and  longer  than  broad.  The 
wings  could  not  have  been  visible  on  the  outside  of  the  body, 
for  the  bones  that  constitute  them  are  proportionally  smaller 
than  those  of  the  Apteryx.  There  was,  therefore,  a  maximum 
reduction  of  the  wing  in  this  bird. 

The  Dinornis  was  covered  with  a  rich  plumage,  and  this 
was  doubtless  what  led  to  its  destruction,  women  preferring  its 
plumes  to  all  other  ornaments.  The  large  number  of  bones 
which  have  been  discovered  in  the  alluviums,  the  caves,  and  the 
peat  bogs  of  New  Zealand  authorize  the  thought  that  the  island 
was  once  inhabited  by  a  considerable  number  of  these  birds, 
which  were  able  easily  to  repel  the  attacks  of  other  animals  by 
means  of  their  big  feet.  But  they  could  stand  no  chance 
against  Nature's  more  terrible  destroyer — man — who,  when 
seeking  the  gratification  of  his  taste  and  fancy,  does  not  hesi- 
tate to  exterminate  whole  species.  The  natives  of  New  Zea- 
land still  recall  the  history  of  these  singular  birds ;  their  exter- 
mination seems  to  have  occurred  about  the  time  the  island  was 


EVOLUTION  AND  NATURE  STUDIES 


391 


visited  by  Captain  Cook  (1767-1778).  Moreover,  some  of  the 
bones  collected  in  later  years  still  had  animal  matter  upon 
them.  Even  parts  of  the  windpipe  have  been  discovered, 
mixed  with  charcoal,  and  evidences  of  cooking  have  been  found. 

A  near  relative  of  the  Dinornis,  which  the  Maoris  regard 
as  extinct,  is  the  Notornis,  of  which  only  four  living  specimens 
have  been  found  since  1842,  the  last  one  having  been  captured 
in  the  latter  part  of  1 898. 

The  eggs  of  the  Dinornis  were  very  large,  having  a  capacity 
of  about  a  gallon  and  being  equivalent  to  eighty  hen's  eggs. 
Still  larger  eggs  than  these,  however,  are  known.  In  1851  Isi- 
dore Geoffroy  Saint-Hilaire  exhibited,  in  the  French  Academy 
of  Sciences,  eggs  of  a  bird  coming  from  Madagascar  that  had 
a  capacity  of  two  gallons.  Some  specimens  of  these  eggs  may 
be  seen  in  the  galleries  of  the  Paris  Museum,  and  still  larger 
eggs  have  been  found.  The  museum  in  London  has  one  with 
a  capacity  exceeding  eleven  quarts,  or  equivalent  to  two  hun- 
dred and  twenty  hen's  eggs,  or  more  than  seventy  thousand 
humming-birds'  eggs.  It  was  thought  at  first  that  the  bird 
which  laid  these  gigantic  eggs  was  still  living,  for  natives  of 
Madagascar  spoke  of  having  seen  a  bird  of  colossal  size  that 
could  throw  down  an  ox  and  make  a  meal  of  it.  Such,  how- 
ever, were  not  the  ways  of  the  bird  called  the  Epiornis,  which 
had  no  talons  or  wings,  and  fed  on  vegetable  substances.  The 
description  by  the  celebrated  traveler  Marco  Polo  of  a  great 
flying  bird  of  prey,  called  a  roc,  has  no  reference  to  the  Epior- 
nis.  M.  Grandidier  has  demonstrated  that  this  bird  no  longer 
exists  in  Madagascar,  and  that,  if  man  ever  knew  it,  the  stories 
with  marvelous  details  which  the  savages  hand  down  from 
generation  to  generation  make  no  mention  of  it.  We  owe  to 
M.  Grandidier,  M.  Milne-Edwards,  and  Major  Forsyth  what  is 
known  of  the  history  of  this  large  wingless  bird,  which  resem- 
bles the  Dinornis  in  several  points.  If  its  size  was  propor- 
tioned to  that  of  its  eggs  it  should  have  been  twice  as  large  as 
the  Dinornis.  It  was  not,  however,  but  constituted  a  family 
represented  by  very  diverse  forms  and  of  variable  size,  though 
never  much  exceeding  eleven  feet.  The  head  was  similar  in 
appearance  to  that  of  the  Dinornis,  but  the  surface  of  the  fore- 


392  ACHIEVEMENTS  IN  SCIENCE 

head  was  furrowed  with  wrinkles  and  cavities,  indicating  the 
presence  of  a  crest  of  large  feathers.  A  curious  peculiarity 
was  the  opening  of  the  Eustachian  tube  directly  on  the  exterior. 
The  cervical  vertebrae  are  very  numerous,  while  the  sternum  is 
much  reduced.  It  is  a  flat  bone,  broad  but  very  short,  espe- 
cially in  the  median  part.  The  wing  also  has  suffered  a  great 
regression,  for  it  comprises  only  a  thin,  short  rod,  the  humerus, 
and  a  small  osseous  mass  representing  all  the  other  bones  of 
the  wing  stuck  together.  The  Epiornis  had  no  wings  exter- 
nally visible.  The  bones  of  the  feet  were,  on  the  other  hand, 
of  considerable  size,  and  indicate  that  the  bird  that  possessed 
them  was  larger  than  the  Dinornis. 

The  Epiornis,  according  to  M.  Milne-Edwards,  frequented 
the  borders  of  waters,  keeping  among  the  reeds  along  lakes 
and  rivers,  for  its  bones  are  found  associated  with  those  of  tur- 
tles, crocodiles,  and  a  small  hippopotamus.  It  most  probably 
nested  in  the  low  plains  around  lakes. 

Just  as  the  Apteryx  among  birds,  and  the  bison  and  the 
beaver  among  mammals,  so  the  Dinornis  and  the  Epiornis  have 
been  destroyed  as  man  has  extended  his  abode  and  his  domina- 
tion. 

When  we  regard  the  fauna  of  Madagascar  and  of  New  Zea- 
land we  are  struck  by  the  great  resemblance  between  them, 
from  the  points  of  view  of  their  recent  and  ancient  vertebrate 
fauna.  These  resemblances  suggest  the  past  existence  of  rela- 
tions between  these  two  lands  now  separated  by  a  wide  expanse 
of  sea,  and  this  agrees  with  geological  observations. 


EVOLUTION  AND  NATURE  STUDIES 


The  Cobra  and  Other  Serpents 

By  G.   R.   O'REILLY 

Corresponding  Member  of  the  Royal  Zoological  Society  of  Ireland 

DURING  a  three  years'  residence  in  southern  Africa  cobras 
and  other  snakes  were  my  pets  and  most  intimate  com- 
panions. They  occupied  my  bedroom ;  they  sunned  themselves 
in  my  windows ;  they  coiled  themselves  in  my  armchair  and  on 
my  study  table,  and  made  themselves  quite  at  home  among  my 
book-shelves  and  bric-a-brac.  Baby  cobras  were  born  into  my 
hands,  and  adult  cobras  accompanied  me,  coiled  in  my  pocket, 
whenever  I  went  out  to  take  sly  observations,  through  a  binocu- 
lar glass,  of  the  movements  of  their  brothers  and  sisters  still 
free  among  the  rocks  and  bushes  of  plain  or  hillside. 

Above  all  his  peers  in  the  ophidian  kingdom,  the  royal  cobra 
claimed  my  chief  attention.  His  beauty,  the  web  of  Oriental 
romance  in  which  his  name  is  intertwined,  and  the  dreadful  de- 
struction of  human  life  with  which  he  is  credited,  make  him  to 
all  of  us  an  exceedingly  interesting  animal.  As  man  alone 
stands  up  and  walks  erect,  the  acknowledged  king  among  living 
things,  so  it  is  only  the  cobra  of  all  the  reptile  kind  that  raises 
himself  perpendicularly  from  the  ground  and  expands  his  neck 
as  if  in  fancied  pride  of  his  power  to  dispute  with  humanity  the 
supremacy  over  animal  life.  Year  after  year,  over  the  whole 
of  Southern  Asia,  but  especially  in  the  Indian  Peninsula,  a  vast 
multitude  of  men,  women,  and  children  fall  victims  to  his  deadly 
fangs.  If  each  year,  within  the  bounds  of  British  India  alone, 
a  town  of  10,000  inhabitants  were  to  be  utterly  depopulated  by 

393 


394  ACHIEVEMENTS  IN  SCIENCE 

a  painful  form  of  death,  and  if  this  calamity  had  been  constantly 
recurring,  as  far  back  through  the  centuries  as  history  has 
record  of,  who  would  not  be  filled  with  commiseration  for  a 
people  so  afflicted  ?  And  yet  in  that  same  country  this  number 
of  human  beings  is  annually  carried  off  by  the  bite  of  poisonous 
serpents,  and  the  world  looks  for  it  as  a  matter  of  course. 
Thus  the  dreaded  cholera  itself  is  not  a  greater  destroyer  of 
human  life,  as  it  is  but  an  occasional  visitant.  As  the  cobra  is 
blamed  for  nearly  all  this  appalling  mortality,  we  need  not  seek 
out  further  reason  for  giving  him  the  title  of  "  king  of  deadly 
serpents." 

Sir  Joseph  Fayrer,  in  his  magnificent  "  Thanatophidia  of  In- 
dia," gives  us  copious  information  regarding  his  poison,  its  ter- 
rible work  among  the  Indian  peoples,  and  the  various  methods 
of  counteracting  its  effects ;  and  more  recently  our  own  able  in- 
quirer, Dr.  Weir  Mitchell,  has  given  us  its  analysis.  But  as 
regards  the  story  of  cobra  life  itself,  cobra  capabilities,  and 
cobra  idiosyncrasies,  we  are  still  at  the  mercy  of  Pliny  and  his 
successors.  From  book  to  book  the  old  yarns  of  his  fondness 
for  milk  and  his  susceptibility  to  music  are  handed  down  as 
heirlooms,  and  will  continue  to  find  believers  until  writing 
naturalists  keep  living  cobras  at  their  elbows. 

Under  the  general  name  "  cobra  "  are  included  several  spe- 
cies, differing  little  in  general  appearance.  They  are  found  all 
over  southern  Asia  and  throughout  the  entire  continent  of 
Africa.  In  India,  Naja  tripudians  is  common ;  in  North  Africa, 
Naja  haja ;  and  in  South  Africa,  Sepedon  hcemachates.  In  the 
other  continents  no  true  cobra  exists.  They  are  all  hooded 
snakes,  and  all  exceedingly  venomous.  In  color  they  vary 
much ;  some  are  yellow,  some  are  brown,  others  black — while 
in  general  all  are  banded  more  or  less  distinctly  with  regular 
light  and  dark  rings.  They  are  usually  about  four  feet  in 
length  and  two  inches  in  diameter,  but  can  attain  to  six  feet. 

All  terrestrial  deadly  serpents  may  be  divided  into  two  groups 
— the  Viperidce,  which  have  the  head  covered  with  small,  irregu- 
lar scales ;  and  the  Elapidcs,  which  have  it  covered  with  large, 
regularly  disposed  plates.  Taking  the  rattlesnake  as  the  repre- 
sentative of  the  Viperida  and  the  cobra  of  the  Elapidce,  it  will 


EVOLUTION  AND  NATURE  STUDIES         395 

be  instructive  to  note  some  of  the  differences  between  these 
two  famous  poisoners.  The  head  in  the  rattler  is  broad  and 
flat  and  the  neck  very  thin ;  its  body  increases  in  diameter 
toward  the  middle  and  gradually  tapers  off  to  the  tail.  In  the 
cobra  the  head,  neck,  and  body  are  of  the  same  thickness  until 
the  tail  commences.  In  the  rattlesnake  the  eyes  have  a  verti- 
cal pupil,  like  a  cat's ;  in  the  cobra  the  pupil  is  round.  In  the 
rattlesnake  the  fangs  are  long,  well  curved,  very  movable,  thin, 
and  with  the  end  of  the  poison  duct  coming  out  almost  in  the 
same  line  with  the  point  of  the  fang ;  in  the  cobra  the  fang  is 
very  short,  slightly  curved,  scarcely  movable,  strong,  and  with 
the  end  of  the  poison  duct  coming  out  at  a  large  angle  with  the 
point.  In  disposition  the  rattler  is  much  more  sluggish  and 
not  nearly  so  timorous  as  the  cobra.  To  meet  an  assailant,  the 
rattlesnake  will  arrange  himself  coiled  carefully,  like  a  spring, 
in  a  horizontal  position ;  while  the  cobra  prepares  no  coil,  but 
raises  himself  up  on  high,  perpendicular  from  the  ground.  As  to 
the  manner  of  securing  their  prey,  the  rattlesnake  is  like  a  cat : 
he  lies  in  wait  for  it  in  a  suitable  locality,  and  then  springs  on 
it  unawares,  generally  waiting  till  its  death  struggles  have 
ceased  before  swallowing  it.  The  cobra,  on  the  contrary,  hunts 
up  his  victims,  pursues  them  like  a  dog,  and  swallows  them 
alive  when  caught.  There  is  also,  as  Dr.  Weir  Mitchell  has 
shown,  a  marked  chemical  variance  between  their  poisons. 

All  these  differences  are,  as  a  rule,  applicable  to  their  re- 
spective classes ;  and  it  is  worthy  of  mention  that  in  the  several 
points  enumerated,  excepting  as  regards  the  poison  arrange- 
ments, the  Viperida  agree  with  the  true  boas  and  the  Elapida 
with  the  colubrine  or  common  harmless  snakes.  So  it  will  be 
understood  that  the  cobra  is  rather  a  cousin  to  the  black  snake 
than  to  the  rattler. 

In  searching  for  his  prey,  he  glides  about  without  anything 
remarkable  in  his  appearance  to  denote  that  he  is  a  cobra; 
but,  when  excited  by  fear  or  anger,  he  raises  his  head  and  from 
one-third  to  one-half  of  his  body  perpendicularly  from  the 
ground,  while  the  remainder  is  gathered  beneath  into  a  coil  of 
support.  At  the  same  time  the  upper  ribs,  from  the  head 
downward  for  five  or  six  inches  or  more,  spread  themselves  out 


396  ACHIEVEMENTS  IN  SCIENCE 

laterally,  carrying  the  skin  with  them,  thus  making  of  his  neck 
a  thin,  flattened  oval  disk  four  or  five  inches  broad.  This  wide 
flatness  of  the  neck  is  called  the  "  hood,"  and  above  it  the  head 
appears  pointing  horizontally  to  the  front.  His  disposition  is 
so  extremely  nervous  and  timid  that  he  will  strike  at  a  moving 
adversary  long  before  he  comes  near  enough  to  reach  him  with 
effect.  If  you  stand  before  a  cobra  thus  erect  and  alarmed, 
and  move  alternately  your  left  and  right  hands  up  and  down, 
he  will  strike  repeatedly  to  the  left  and  right,  following  your 
motions,  bringing  his  head  and  neck  flat  on  the  ground  each 
time,  and  at  every  stroke  drawing  closer  to  you.  In  striking 
thus  he  hisses  audibly  and  instantly  reassumes  his  erect  posi- 
tion, and  thus  he  continues  to  act  as  long  as  danger  menaces 
or  a  safe  avenue  of  escape  does  not  present  itself.  This  turn- 
ing to  the  left  and  right  after  one's  movements  and  striking 
downward  is  the  so-called  "  dancing,"  which  superficial  observers 
have  attributed  to  the  power  of  music.  Even  after  a  slight 
acquaintance  with  snake  dancing  I  began  to  suspect  that  music 
had  nothing  to  do  with  it.  Before  long  I  was  convinced  on  the 
subject. 

It  happened,  I  believe,  in  1877,  that  Sir  Bartle  Frere,  Gov- 
ernor of  the  British  dominions  in  South  Africa,  when  on  his 
way  eastward  to  settle  some  troubles  preceding  the  outbreak 
of  the  war  with  the  southern  Kaffirs,  paid  a  visit  to  my  collec- 
tion at  Grahamstown.  He  arrived  unexpectedly  and  found 
me  on  my  knees  with  my  sleeves  rolled  up,  washing  out  my 
floor,  for  it  was  impossible  to  get  a  servant  to  enter  the  room. 
Seeing  there  all  the  snakes  of  the  country  living  before  him, 
he  was  intensely  interested,  and  at  once  singled  out  the  cobra 
as  an  old  acquaintance,  for  he  had  spent  much  of  his  life  in 
India.  Many  things  he  told  me  of  Indian  snake-charming; 
but  when  I  made  the  cobras  dance,  faint  away  as  if  dead,  and 
by  a  touch  return  them  to  life  again,  he  asked  in  some  aston- 
ishment how  it  happened  that  I  did  so  without  the  aid  of  music. 
I  explained  the  "  dancing  "  as  the  natural  tactics  of  the  cobra 
in  defense  and  attack,  and  the  fainting  and  recovery  as  conse- 
quences of  an  extremely  nervous  and  over-excitable  tempera- 
ment. But  my  visitor  clung  to  his  old  opinion,  saying  that  my 


EVOLUTION  AND  NATURE  STUDIES          397 

belief  that  they  never  really  danced  to  the  music  was  opposed 
to  the  teachings  of  natural  history  and  to  the  experience  of 
every  one  who  had  lived  in  India. 

Next  day,  when  the  astute  Sir  Bartle  was  on  his  way  to  the 
frontier  to  charm  the  turbulant  chiefs  with  diplomacy,  I  invited 
a  flute-player  to  charm  my  snakes.  I  myself  went  into  the 
room  to  note  results  and  sat  down  in  my  usual  place  among 
my  pets,  leaving  the  musician  outside  in  the  hall,  so  placed 
that  the  snakes  could  not  see  him.  He  played  his  sweetest 
tunes.  The  "Last  Rose  of  Summer,"  "Annie  Laurie,"  and 
"  Home,  Sweet  Home  "  had  no  effect,  so  I  called  to  him  to  play 
something  quick  and  lively.  Accordingly,  he  gave  us  "  Pop 
goes  the  Weasel,"  "Miss  McLeod's  Reel,"  and  "The  White 
Cockade  " ;  but  never  a  snake  moved.  I  then  invited  him  in- 
side, but  the  result  was  the  same,  the  flute  was  a  failure.  Next 
day  I  tried  the  violin.  The  performer  again  sat  outside,  but 
all  his  efforts  were  useless ;  both  quick  and  slow  music  were 
alike  lost  upon  them.  On  my  invitation  he  came  in  and  sat 
still  a  few  moments  preparatory  to  commencing  afresh.  He 
soon  thought  himself  an  Orpheus ;  for,  as  he  began  playing, 
the  cobras  stood  upon  the  floor.  "  Aha ! "  said  he,  "  see  that ! " 
However,  believing  that  they  were  only  alarmed  at  the  quick 
movements  of  his  arm,  I  stood  over  between  him  and  them, 
thus  cutting  off  their  view,  whereupon  they  showed  that  their 
fears  were  quieted  by  gently  lowering  themselves  to  the  floor. 

On  the  table  was  a  glass-fronted  wooden  box  in  which  was 
a  large  puff  adder.  I  got  the  musician  to  sit  close  opposite  to 
this  and  play  his  loudest,  but  the  snake  never  showed  the 
slightest  sign.  Then,  at  my  request,  he  went  round  behind  the 
cage  and  let  one  end  of  the  violin  rest  on  the  top  of  it.  At 
first  he  played  the  higher  notes,  and  the  snake  showed  no  sign ; 
but  when  he  touched  the  deep  bass  chords  the  animal  swelled 
himself  up  and  began  to  blow  as  if  alarmed.  Thus,  from  the 
instrument  resting  on  the  wood  of  the  top,  the  vibration  was 
conveyed  to  the  whole  box,  and  the  snake  felt  it  throughout  his 
entire  body  where  he  lay  in  contact  with  it,  in  the  very  same 
way  that  I  myself  felt  it  when  I  laid  my  hand  upon  it. 

Many  trials  were  made  with  other  instruments,  but  always 


398  ACHIEVEMENTS  IN  SCIENCE 

with  the  same  results,  viz.,  i .  Music  from  an  unseen  performer 
had  no  effect  whatever.  2.  If  the  performer  were  seen,  any 
noticeable  movements  of  his  would  alarm  the  snakes,  but  in 
exactly  the  same  way  as  if  he  made  no  noise  at  all.  3.  They 
gave  signs  of  disturbance  when  the  vibration,  especially  of  bass 
sounds,  was  communicated  to  the  material  on  which  they 
lay. 

Thus  was  proved  not  only  that  cobras  do  not  dance  to 
music,  but  that,  far  from  being  charmed  with  the  melody,  the 
poor  animal  is  only  frightened  at  the  movements  of  the  musi- 
cian, and  that  the  apparent  dancing  and  bowing  are  only  so 
many  half-hearted  attempts  to  strike  at  the  performer  or  some 
one  moving  in  his  vicinity.  Furthermore,  I  was  led  to  the 
conclusion  that  snakes  cannot  hear  any  sound with  sufficient 
distinctness  to  determine  their  acts,  unless  it  is  so  great  as  to 
cause  objects  in  contact  with  their  skin  to  vibrate  sensibly  to 
the  touch,  and  that  even  then  they  can  only  be  said  to  feel  the 
sound's  effect. 

At  the  present  moment,  as  I  write,  there  is  on  the  table  be- 
fore me  a  glass-fronted  box  in  which  are  some  of  our  common 
garter  snakes.  On  the  top  of  this  box  is  placed  an  alarm  clock. 
Now,  when  the  alarm  goes  off  in  this  position  the  garters 
always  move  a  little,  for  the  vibration  is  communicated  to  the 
wood  and  can  be  plainly  felt  with  the  finger-tips ;  but,  when  the 
clock  is  on  the  cloth-covered  table  close  by  and  not  in  contact 
with  the  wood  on  which  they  lie,  they  never  give  a  sign  of 
having  heard  it. 

When  I  lived  on  the  island  of  Trinidad,  I  had  a  large  collec- 
tion of  West  Indian  and  South  American  serpents  which  it  was 
necessary  to  feed  on  animals  of  many  different  species.  It  was 
always  noticeable  that  neither  boa,  viper  elaps,  nor  coluber 
ever  gave  the  slightest  heed  to  the  voices  of  these,  while  at 
sight  of  the  moving  prey  they  manifested  very  evident  signs  of 
recognition.  Snakes,  as  a  rule,  are  very  timid,  and  as  I  often 
had  visitors  at  feeding  time,  it  used  to  be  necessary  to  warn 
them  that  any  stirring  about  of  arms  or  legs  would  be  sure  to 
delay  the  dinner;  but  no  restriction  was  ever  needed  to  be 
placed  on  conversation,  except  that  the  turning  of  the  head 


EVOLUTION  AND  NATURE  STUDIES          399 

was  forbidden — each  had  to  talk  straight  to  his  front,  no  mat- 
ter whom  he  addressed. 

During  the  past  four  or  five  years  I  have  hunted  extensively 
over  the  woods  of  northern  South  America,  from  the  Bay  of 
Panama  to  the  Delta  of  the  Orinoco,  often  alone,  sometimes 
with  others.  Now,  when  I  had  company  it  would  be  frequently 
necessary  to  call  on  their  assistance  in  capturing  some  of  the 
long,  swift-running  snakes.  If  one  of  these  were  discovered 
some  distance  off,  resting  close  by  a  fallen  tree,  it  was  my 
method  to  go  round  to  the  other  side  of  the  old  trunk  and  come 
up  unseen,  often  within  a  yard  of  him.  There  I  would  shout 
directions  to  my  friends,  sometimes  at  the  top  of  my  voice, 
where  to  post  themselves  and  where  to  head  him  off.  This 
shouting  never  caused  the  snake  to  stir ;  but  should  I  show  the 
rim  of  my  hat  moving  up  even  a  hand's  breadth  over  the  inter- 
vening trunk,  he  would  be  off  like  a  race-horse ;  for  the  eyes  of 
a  serpent,  though  dull  to  note  form  and  color,  are  exceedingly 
quick  to  detect  motion. 

Now,  it  may  be  mentioned  that  snakes  have  no  external 
ears,  their  heads  being  entirely  covered,  like  the  rest  of  the 
body  with  a  tough  and  scaly  skin.  Yet  in  how  far  they  may 
be  able  to  detect  sound  waves  in  the  air,  as  a  general  evidence 
of  something  unusual,  with  the  delicate  tip  of  the  restless  bifid 
tongue,  is  a  subject  that  requires  investigation ;  but  that  they 
can  appreciate  music  in  this  or  any  other  way  is,  as  has  been 
said  above,  absolutely  untrue.  How  such  an  idea  as  that 
snakes  are  fond  of  music  and  milk  ever  gained  credence  among 
men  calling  themselves  scientists  only  shows  how  few  really 
scientific  observers  we  have. 

Men  sometimes  do  strange  things  for  the  love  of  knowl- 
edge, and  it  was  this  love  which  caused  me  to  live  on  such  inti- 
mate terms  with  my  scaly  but  graceful  and  gentle  friends.  I 
took  them  into  my  house  to  live  with  me.  This  was  the  best 
way  to  know  them  perfectly ;  and  the  more  I  knew  them,  the 
more  I  knew  that  they  did  not  know  me.  I  soon  found  out 
that  neither  cobras  nor  any  other  serpents  can  ever  become 
capable  of  attachment,  nor  even  distinguish  one  person  from 
another,  nor  distinguish  a  man  from  any  large  animal,  nor  even 


400  ACHIEVEMENTS  IN  SCIENCE 

distinguish  a  man  from  a  tree  stump  until  he  gives  evidence  of 
his  life  by  motion. 

During  my  stay  in  South  Africa  I  had  many  cobras,  all  of 
which  I  captured  myself,  except  those  born  in  my  collection. 
Now,  cobra-hunting  is  a  very  dangerous  kind  of  sport,  and  had 
I  known  of  its  perils  otherwise  than  by  experience  it  is  proba- 
ble that  I  never  would  have  attempted  it.  The  first  two  or 
three  I  caught  safely,  and  nothing  particular  occurred  to  show 
that  there  was  a  special  danger  in  taking  them  which  did  not 
equally  exist  in  the  capture  of  other  deadly  snakes.  But  I 
found  out  that  in  three  important  particulars  of  defense  and 
attack  the  cobra  differs  from  all  his  fellow-poisoners : 

I.  He  rarely  opens  his  mouth  when  striking,  but  actually 
gives  a  deadly  blow  without  biting.  2.  He  bites  deliberately 
when  he  is  in  a  state  of  apparent  death  from  muscular  contor- 
tion, and  will  then  hang  on  like  a  bulldog,  the  venom  flowing 
all  the  time  into  the  wounds  in  which  his  fangs  are  buried 
until  he  drops  off  at  last  from  sheer  exhaustion.  3.  He  can 
squirt  the  venom  from  his  fangs  into  a  person's  eyes,  and  thus 
blind  him  for  a  time  at  least. 

I  had  often  heard  of  the  "  spuugh  slang,"  or  spitting  snake, 
but  looking  at  the  thing  from  a  too  human  point  of  view — as 
we  are  all,  unfortunately,  overmuch  inclined  to  do  when  con- 
sidering animals — I  could  not  understand  how  a  snake,  not 
having  fleshy  lips  and  a  bulky  tongue,  could  be  said  to.  spit  as 
we  understand  the  word ;  and  hence  could  no  more  believe  in 
spitting  snakes  than  I  would  in  unicorns  or  fiery  dragons. 
However,  the  result  proved  that  oftentimes  a  story  which  on 
the  face  of  it  seems  impossible  has,  after  all,  a  certain  fund  of 
truth  lying  concealed  somewhere  at  bottom. 

One  day,  being  alone  in  the  bush,  I  saw  a  cobra  banded 
with  black  and  white.  He  was  in  an  open  glade,  gliding  about 
through  the  herbage,  delaying  a  little  perhaps  for  an  opportunity 
to  get  at  some  birds  that  were  chattering  and  hopping  about 
on  the  branches  of  a  thorny,  yellow-blossomed  acacia.  The 
sun  was  blazing  down  fiercely  on  him  as,  with  half-distended 
hood  held  close  to  the  ground,  he  slowly  passed  through  the 
leaves  and  flowers.  For  a  few  minutes  I  watched  his  move- 


EVOLUTION  AND  NATURE  STUDIES 


401 


ments  through  my  binocular  glass ;  but,  fearing  he  might  notice 
me  and  escape  into  some  hole,  I  picked  up  my  six-foot  hunting 
stick  and  rushed  toward  him,  intending  to  press  his  head  to  the 
ground  with  it,  and  then  take  him  by  the  neck  with  my  hand. 
He  saw  me  coming,  and,  like  a  valiant  warrior  that  knew  his 
power,  he  faced  round  and  stood  erect  with  expanded  hood  and 
quivering  tongue  ready  to  receive  me.  His  bright  black  eyes 
sparkled  with  energetic  defiance,  and  every  fiber  of  his  being 
was  electrified  with  excitement.  While  I  was  yet  ten  feet 
away  he  struck  toward  me  with  such  force  that  the  impetus 
carried  him  flat  to  the  ground.  As  I  tried  to  get  my  stick  across 
his  neck  he  dodged  it,  and  it  came  instead  across  the  middle  of 
his  body.  At  this  moment  he  was  between  me  and  the  sun, 
with  about  five  feet  between  his  face  and  mine.  I  looked  into 
his  eyes  and  held  him  down  firmly.  His  rage  seemed  re- 
doubled. He  leaned  backward  to  make  a  more  vigorous  dash 
at  me,  and  as  he  struck  forward  the  mouth  partially  opened,  and 
two  tiny  streams  of  venom  shot  from  his  fangs  as  from  a  syringe, 
one  of  them  catching  me  on  the  face  just  beneath  the  eye. 
Had  it  gone  a  little  higher  up  I  should  have  been  blinded  for 
months,  and  perhaps  had  my  sight  permanently  injured.  This 
unexpected  attack  made  me  hasten  the  capture ;  so,  getting  his 
neck  pressed  down  to  the  ground  with  the  stick,  I  soon  had 
him  grasped  in  my  hand  just  behind  the  head  in  such  a  way 
that  he  couldn't  possibly  turn  to  bite  me — which  he  made  every 
effort  to  do  for  some  minutes  afterward.  Taking  him  home 
with  much  satisfaction,  I  made  him  thereafter  my  fellow-lodger. 
While  living  in  his  cage,  I  observed  him  many  times  squirt  the 
venom  from  his  fangs  against  the  glass  of  its  front.  Thence- 
forth my  doubts  about  spitting  snakes  were  removed. 

In  order  to  understand  how  it  is  that  he  can  eject  the  venom 
as  high  as  a  person's  face — which  we  never  hear  of  the  viperine 
snakes  doing — it  is  well  to  consider  carefully  the  approximate 
difference  in  the  fangs  of  the  cobra  and  those  of  the  rattler. 
Snakes  of  the  class  Viperidce  can,  and  do  under  certain  circum- 
stances, eject  the  venom  somewhat  similarly,  but  their  methods 
of  striking  are  more  deliberate  usually,  and  instead  of  the  first 
and  more  copious  discharge  being  thus  lost,  as  is  often  the 
26 


402  ACHIEVEMENTS  IN  SCIENCE 

case  with  the  cobra,  it  is,  on  the  contrary,  injected  into  the 
veins  of  enemy  or  prey.  This  premature  squirting  out  of  the 
fluid  in  the  cobra  is  not  to  be  taken  as  a  voluntary  act.  It  has 
been  mentioned  above  that  he  is  so  excitable  that  he  will  strike 
at  a  moving  adversary  long  before  he  comes  near  enough  to 
actually  hit  his  object ;  and  it  is  in  striking  thus  from  a  distance 
that  the  poison-controlling  muscles  act  as  if  he  really  struck 
something,  and  the  distended  gland  gives  way  to  the  pressure, 
forcing  the  contents,  which  in  other  circumstances  would  have 
been  injected  into  the  flesh,  to  go  instead  in  two  thin  streams 
through  the  air. 

In  regard  to  the  manner  in  which  the  cobra  strikes  with 
effect  without  opening  his  mouth,  it  is  necessary  to  state  that 
while  the  fangs  of  the  rattlesnake  and  other  viperine  snakes 
are  laid  horizontally  back  along  the  upper  jaw  when  the  mouth 
is  closed  and  only  erected  when  the  mouth  is  widely  open,  it  is 
not  so  in  the  cobra ;  but  whether  his  mouth  be  open  or  shut, 
his  fangs  are  always  partially  or  wholly  erect,  and  not  in  the 
true  sense  of  the  word  reclinable.  Now,  usually  when  he 
strikes  at  an  adversary  his  mouth  does  not  open  as  does  the 
rattlesnakes,  but  he  simply  hits  with  his  chin  the  point  he  aims 
at,  so  that,  the  mouth  being  still  shut  and  the  fangs  during  the 
act  coming  out  over  and  slightly  below  the  lower  lip,  these  pro- 
truding fang-points  penetrate  the  skin,  while  at  the  same  in- 
stant the  potent  venom  is  squirted  with  force  through  these 
natural  hypodermic  syringes  into  the  superficial  punctures. 
Hence  it  is  that  on  the  bare  legs  of  the  natives  this  so-called 
"  bite  "  is  usually  fatal,  while  the  slight  protection  of  trousers 
saves  the  European  from  danger. 

As  to  the  third  peculiarity  of  this  snake — viz.,  the  fit  of 
temporary  lockjaw  into  which  he  is  liable  to  fall  and  the  terri- 
bly prolonged  and  real  bite  he  can  give  when  in  that  state — the 
account  of  an  interesting  adventure  I  once  had  will  give  a  fitting 
illustration.  It  was  a  most  wonderful  exhibition  of  reptilian 
hysterics. 

In  the  midst  of  a  South  African  summer,  when  the  springs 
and  rivers  are  dried  up,  the  snakes  congregate  in  unusual  num- 
bers around  the  dams  which  are  built  by  the  colonists  to  store 


EVOLUTION  AND  NATURE  STUDIES          403 

up  in  the  ravines  for  themselves  and  their  cattle  the  drinking 
supply  afforded  during  the  rains  by  the  mountain  torrents.  At 
one  of  these  reservoirs  in  Currie's  Kloof,  near  Grahamstown,  I 
had  secured  several  fine  serpents,  and  was  not  surprised  there- 
fore when  one  afternoon,  as  I  was  sitting  by  an  upper  window, 
I  saw  a  boy  running  from  that  direction  toward  the  house, 
shouting  as  loud  as  he  could  bawl,  "  A  snake,  sir — a  monster 
snake!" 

I  ran  downstairs  and  found  him,  breathless  and  pale  with  ex- 
citement, at  the  door.  The  snake,  he  said,  was  fully  twenty 
feet  long.  It  had  pursued  him  a  little  way  through  the  bushes 
and  then  disappeared  in  a  hole  in  the  bank.  "  Aha !  "  thought 
I,  "  this  must  be  the  great  Natal  python  I  have  heard  so  much 
about  but  never  seen."  With  some  doubts,  nevertheless,  about 
his  being  twenty  feet  long — for  people  usually  imagine  snakes 
which  scare  them  to  be  much  bigger  than  they  really  are — I 
took  my  snake-hunting  stick  and  set  off  at  once  to  make  the 
capture.  On  arriving  at  the  pond,  which  was  overhung  by 
poplar  trees  and  nearly  dried  up,  the  boy  led  me  across  a  long 
stretch  of  hardened,  sunbaked  mud  to  a  point  in  the  great 
earthen  dam  about  twenty  feet  over  from  the  water's  edge, 
where  there  was  a  hole,  the  mouth  of  which  he  had  carefully 
stopped  up  with  a  good-sized  stone  before  coming  to  tell  me. 
This  I  removed,  and  as  the  snake  was  not  there  ready  to  bolt 
out  as  I  expected,  I  ran  in  the  stick  to  dislodge  him.  This, 
however,  had  no  effect.  So,  taking  a  piece  of  stout  paling  wire, 
I  made  with  it  a  hook  to  the  end  of  my  snake  stick.  Running 
in  this  arrangement,  I  managed  to  catch  it  in  his  folds,  a  pro- 
ceeding which  he  resented  by  slipping  it  off  and  by  many  angry 
hissings  which  sounded  all  the  louder  from  being  uttered  in  the 
confinement  of  his  subterranean  retreat.  After  several  failures 
he  was  at  last  hauled  out.  "  A  cobra,  by  Jove ! "  said  I,  as  he 
raised  himself  up  erect  with  expanded  hood  on  the  hard  mud 
expanse  between  me  and  the  water.  As  his  head  when  stand- 
ing thus  was  fully  eighteen  inches  high,  it  was  no  easy  matter 
to  press  his  neck  to  the  ground  so  as  to  catch  him  safely  with 
my  hand.  Without  at  all  hurting  him  I  made  several  attempts 
to  get  his  neck  down,  and  not  without  some  nervousness,  for 


404  ACHIEVEMENTS  IN  SCIENCE 

he  might  at  any  moment  send  a  charge  of  venom  into  my  face. 
This  playing  him  with  the  stick  to  get  him  into  proper  position 
so  aroused  and  alarmed  him  that  at  last,  overcome  by  his  own 
excitement,  he  suddenly  collapsed,  falling  over  on  his  side  and 
lying  there  motionless,  half  on  his  back,  with  his  mouth  fixedly 
open  and  stiff  as  if  in  death.  His  whole  body  was  rigidly  con- 
torted and  as  unbending  as  a  dried  stick.  "  Ah,  you've  killed 
him ! "  shouted  the  boy  from  the  top  of  the  dam,  whither  he 
had  retreated  for  safety.  However,  as  I  had  seen  this  mani- 
festation before,  I  knew  that  it  was  only  an  hysterical  fit. 
Warning  the  lad  not  to  approach,  I  picked  up  the  apparently 
lifeless  snake  by  the  tail-tip  and  flung  him  off  from  me  to  a 
distance  of  five  or  six  feet.  As  soon  as  he  touched  the  ground 
all  his  life  was  active  again.  Up  he  stood  instantly  with  ex- 
panded hood  as  before,  the  black  eyes  glistening  angrily  and 
the  forked  tongue  running  out  quiveringly  from  the  closed 
mouth  as  if  daring  me  to  approach.  A  slight  touch  with  the 
stick  on  the  neck  caused  him  to  fall  down  in  a  second  fit  similar 
to  that  from  which  he  had  just  recovered.  There  he  lay  again, 
to  all  appearance  dead,  with  every  muscle  rigid  and  his  jaws 
fixed  in  a  partial  gape  as  if  sudden  dissolution  had  prevented 
their  closing.  Seeing  in  this  an  opportunity  of  giving  the  boy 
a  lesson  against  the  danger  of  meddling  with  seemingly  dead 
cobras,  I  called  him  down  to  my  side.  "  Do  you  think  that 
snake  is  dead  ? "  said  I. 

"  Yes,"  he  replied,  "I  believe  he  is  surely  dead  now;  you 
must  have  given  him  his  death  wound  getting  him  out  of  the 
hole." 

"  Well,  my  boy,  I'll  show  you  whether  he  is  dead  or  not ; 
and  from  what  you  will  see,  take  warning  that  a  bite  from  an 
apparently  dead  cobra  like  this  is  a  thousand  times  worse  than 
if  he  were  to  strike  you  perchance  in  the  usual  way  as  you  pass 
through  the  bush." 

So  saying,  I  put  the  end  of  the  stick  into  the  stiff,  gaping 
jaws.  Instantly  they  closed  on  it  like  a  vise  until  the  fangs 
were  buried  in  the  wood.  Then,  lifting  him  up  till  his  tail 
swung  clear  of  the  ground,  I  bade  the  boy  count  the  time  by 
his  watch,  to  see  how  long  he  would  retain  his  bulldog-like 


EVOLUTION  AND  NATURE  STUDIES         405 

grip.  The  body  was  gathered  into  unbending  curves ;  but,  as 
the  minutes  went  by,  these  straightened  out,  commencing  at 
the  tail  and  advancing  gradually  upward  to  within  three  inches 
of  the  head.  At  last  this  too  became  limber,  the  jaws  unloos- 
ened, and  he  dropped  to  the  ground  as  the  boy  exclaimed : 
"Well,  I'll  be  blamed!  that  bulldog  snake  held  on  for  eight 
minutes  and  a  half."  As  he  lay  now  exhausted  on  the  ground 
he  put  out  his  tongue  at  intervals,  but  never  otherwise  moved 
until  I  attempted  to  put  the  stick  across  his  neck  preparatory 
to  taking  him,  when  he  stood  up  for  fight  as  fresh  as  ever. 
However,  I  was  nimble  with  the  stick,  and  by  its  aid  got  my 
fingers  round  his  throat  just  as  he  went  into  his  third  fit,  and 
held  his  deadly  jaws  open  again  ready  to  close  upon  anything 
they  should  chance  upon.  Thus  open-mouthed  he  remained  as 
I  carried  him  homeward,  but  recovered  from  his  fit  as  he  was 
placed  in  his  cage. 

The  fears  of  the  boy  had  quadrupled  the  animal's  size,  but 
still  for  a  cobra  he  was  large,  being  considerably  over  four  feet 
in  length.  Having  him  now  at  home  to  practice  on,  I  soon 
learned  how  to  throw  him  into  this  state  of  temporary  lockjaw, 
and  instantly  restore  him  again  at  pleasure.  And  besides  this, 
I  became  certain  that  the  ordinary  wounds  made  by  a  cobra  are 
nothing  compared  with  his  terrible  bite  when  in  this  strange 
condition. 

Among  my  collection  I  had  at  first  six  cobras.  They  used 
to  eat  frogs  and  toads,  pursuing  them  around  the  room  as  a 
dog  would  a  rat,  seizing  them  by  whatever  part  they  could 
catch  hold  of,  and  swallowing  them  down  whole  and  alive. 
After  a  time  the  family  increased,  for  one  Saturday  night  an 
old  lady  cobra  surprised  me  by  depositing  on  the  dressing-table 
a  number  of  living  young  ones  about  as  thick  as  a  large  cigar- 
ette and  seven  inches  long.  In  these  little  snakelings  the  in- 
stinct of  self-defense  was  born ;  for,  before  they  were  a  minute 
old,  they  stood  up  erect,  ready  to  strike  like  their  parents. 
They  were  provided  with  poison,  too,  but  could  not  expand 
their  hoods  till  they  were  a  week  older. 

Dear,  pretty,  little  venomous  babies ! — infant  criminals  of 
the  reptile  kind — they  had  no  more  knowledge  of  nor  affection 


406  ACHIEVEMENTS   IN  SCIENCE 

for  their  mamma  than  if  she  were  an  old  tree-root  or  something 
else  inanimate  lying  in  their  way  and  troublesome  to  be  climbed 
over.  Nor  would  the  mother  take  the  slightest  notice  of  her 
interesting  family.  Indeed,  some  of  them  she  never  saw  at  all. 
Most  probably  she  didn't  know  that  they  were  any  relations  of 
hers,  or  she  would  have  shown  them  some  little  attention. 


EVOLUTION  AND  NATURE  STUDIES 


The  Serpentlike  Sea-Saurians 

By  WILLIAM  H.  BALLOU 

IN  the  latter  part  of  the  Mesozoic  Age  there  was  a  great  in- 
land ocean,  spreading  over  a  large  part  of  the  present  con- 
tinent. The  lands  then  above  water  were  covered  with  a  flora 
peculiar  to  the  times,  and  were  inhabited  by  some  of  the  ani- 
mals which  later  distinguished  the  Cenozoic  age.  In  the  seas 
were  reptiles,  fishes,  and  turtles  of  gigantic  proportions,  armed 
for  offense  or  defense.  There  were  also  oyster-like  bivalves, 
with  enormous  shells,  three  or  four  feet  in  diameter,  the  meat 
of  which  would  have  fed  many  people.  In  time,  this  great 
ocean,  swarming  with  vigorous  life,  disappeared.  Mountain 
ranges  and  plains  gradually  arose,  casting  forth  the  waters  and 
leaving  the  monsters  to  die  and  bleach  in  Tertiary  suns.  As 
the  waters  remaining  divided  into  smaller  tracts,  they  gradually 
lost  their  saline  stability.  The  stronger  monsters  gorged  on 
the  weaker  tribes,  until  they,  too,  stranded  on  rising  sand  bars, 
or  lost  vitality  and  perished  as  the  waters  freshened.  In  imagi- 
nation, we  can  picture  the  strongest,  bereft  of  their  food  supply 
at  last,  and  floundering  in  the  shallow  pools  until  all  remaining 
mired  or  starved.  It  would  be  interesting  to  know  how  much 
of  the  great  Cretaceous  ocean  forms  a  part,  if  any,  of  the  vast 
oceans  of  to-day.  If  any  part  so  survived,  what  became  of  the 
saurians  carried  forth  into  new  ocean  areas?  Were  they 
beaten  on  jagged  rocks  by  powerful  currents  and  destroyed,  or 
did  some  of  them  escape  only  to  perish  in  after  ages  ?  Water, 
as  a  rule,  seeks  its  level ;  sometimes  it  is  evaporated.  If  the 
Cretaceous  ocean  merely  drained  off  into  other  areas  before 

407 


408  ACHIEVEMENTS  IN  SCIENCE 

rising  lands,  it  is  perhaps  not  unreasonable  to  suppose  that  the 
descendants  of  some  of  the  saurians  might  have  survived  in  the 
Atlantic  or  Pacific  as  they  had  existed  in  the  Mesozoic  Age. 
We  can  therefore  only  assume  that  the  Cretaceous  seas  evapo- 
rated or  gradually  freshened  until  all  the  life  they  contained 
became  extinct. 

During  the  past  twenty-five  years  explorers  have  collected 
tons  of  skeletons  of  the  stranded  sea-serpents,  or  better,  per- 
haps, serpent-like  sea-saurians.  A  sensational  world  has  ever 
been  on  the  lookout  for  sea-serpents.  It  is  possible  that 
such  tendencies  are  inherited  from  a  very  remote  ancestor,  a 
primeval,  man-like  animal,  whose  curiosity  was  aroused  by 
glimpses  of  some  surviving  pythonomorph. 

Almost  everywhere  on  the  expanse  of  the  Cretaceous  ocean 
might  have  been  seen  the  snake-like  forms  of  the  elasmosaurs, 
the  heads  arrow-shaped,  upheld  by  swan-like  necks,  rising  from 
ten  to  twenty  feet  above  the  surface  and  scanning  the  sea  or 
air  for  prey  or  enemies.  The  prey  located  below,  they  dived ; 
the  enemy  seen  approaching,  they  swam  away  with  incredible 
speed.  A  flock  of  them  must  have  resembled  the  shipping  of 
a  harbor  with  tall  masts  yellowing  in  the  sunlight.  At  the 
base  of  the  long  necks  were  elephantine  bodies,  and,  behind, 
long,  tapering  tails.  Forward  and  behind  were  two  sets  of 
paddles,  perhaps  terminating  with  webbed  digits.  With  the 
forward  paddles  Cope  thought  that  they  might  have  seized 
prey;  with  all  four  paddles  they  swam.  From  thirty  to  sixty 
feet  in  length,  they  were  well  adapted  to  the  deepest  waters 
and  to  breast  the  waves  of  the  seas.  Like  swans  and  Floridian 
snake-birds,  they  plunged  their  necks  downward  for  prey,  the 
body  perhaps  remaining  on  the  surface  as  an  anchor.  Carnivo- 
rous, the  elasmosaur  ate  what  it  could  seize,  and  to-day,  with 
its  bones,  are  found  the  bones  of  its  victims,  usually  fishes. 
Somewhat  similar  were  the  cimoliosaurs,  even  longer-necked  at 
times,  but  with  shorter  and  more  powerful  tails.  Their  pad- 
dles were  long,  and  as  swimmers  they  must  have  had  few 
equals  in  speed.  Smooth  siliceous  pebbles  to  the  amount  of  a 
peck  or  two  have  been  found  in  numerous  instances  associated 
with  the  remains  of  plesiosaurs  of  various  kinds.  They  evi- 


I 


EVOLUTION  AND  NATURE  STUDIES         409 

dently  formed  a  part  of  the  contents  of  their  stomachs,  but 
their  use  is  not  clear.  But  the  real  rulers  of  the  Cretaceous 
ocean  were  the  pythonomorphs,  or  mosasaurs,  more  like  the 
typical  serpents  of  to-day,  and  more  entitled  to  be  called  sea- 
serpents. 

The  mosasaurs  were  more  elongated  and  graceful  in  form. 
Their  heads  were  large,  flat,  and  conical,  with  the  eyes  directed 
laterally.  The  tails  were  long.  They  had  fore  and  aft  paddles 
with  webbed  digits,  attached  to  the  body  with  wide  peduncles. 
With  paddles  and  flattened  tails  they  swam  with  ease  and 
speed.  Like  snakes,  they  had  four  rows  of  formidable  teeth 
on  the  roof  of  the  mouth,  not  for  mastication,  but  for  seizing 
prey  and  holding  it.  Like  snakes,  they  swallowed  their  prey 
entire,  but,  unlike  snakes,  they  had  not  elastic  throats.  The 
jaw  was,  however,  so  articulated,  jointed  so  far  back  between 
the  ear  and  chin,  ball-and-socket  fashion,  that  the  immense 
opening  made  up  for  the  lack  of  expansibility  of  throat.  The 
ends  of  the  jaws  were  bound  by  flexible  ligaments,  permitting 
the  passage  of  large  fish  or  other  prey.  The  mouth  of  the 
gullet  was  prolonged  forward  while  swallowing,  evidently  being 
loose  and  baggy.  The  same  habit  pushed  forward  the  glottis, 
or  opening  of  the  windpipe  in  front  of  the  gullet.  Like  a  ser- 
pent, the  mosasaur  hissed,  owing  to  these  formations.  The 
tongue  was  long  and  forked,  and  when  at  rest  was  inclosed  in  a 
sheath  beneath  the  windpipe  and  thrown  out  when  the  jaws 
were  in  motion.  And  thus,  too,  are  the  nearest  living  forms. 

The  mosasaurs  attained  great  length,  reaching  from  ten 
to  fifty  feet.  They  had  long,  projecting  muzzles,  somewhat 
like  that  of  the  blunt-nosed  sturgeon  of  to-day,  although  the 
branches  of  the  lower  jaw  were  correspondingly  massive.  With 
such  ramlike  jaws  the  mosasaur  possessed  terrible  powers  of  col- 
lision. They  were  scaled  animals,  and  fragments  of  their  hides 
and  scales  have  been  found  in  good  condition  of  preservation. 

The  first  mosasaur  discovered  was  found  by  Major  Drouin 
in  1776,  on  the  banks  of  the  river  Meuse,  near  Maestricht, 
Germany.  On  this  specimen  was  founded  the  genus  Mosa- 
saurus,  given  it  by  Conybeare  in  1822,  although  the  skele- 
ton was  previously  described  by  Cuvier  in  1808.  The  inter- 


410  ACHIEVEMENTS  IN  SCIENCE 

esting  history  of  the  specimen,  which  created  a  profound  sen- 
sation in  the  world  of  learning  and  became  mixed  up  in  the  his- 
tory of  nations,  is  herewith  reduced  from  Owen.  The  skull 
was  founded  in  the  quarries  of  St.  Peter's  Mount  by  M.  Faujas 
Saint-Fond,  Commissary  for  Sciences  of  the  French  Army  of 
the  North.  In  one  of  the  galleries  or  subterraneous  quarries 
in  which  the  cretaceous  stone  of  St.  Peter's  Mount  was  worked, 
about  five  hundred  paces  from  the  entrance  and  ninety  feet  be- 
low the  surface,  the  quarrymen  exposed  part  of  the  skull  in  a 
block  of  the  stone  which  they  were  engaged  in  detaching.  On 
this  discovery  they  suspended  work  and  went  to  inform  Dr. 
Hofmann,  surgeon  of  the  forces  of  Maestricht,  who  for  some 
years  had  been  collecting  fossils  at  this  quarry,  remunerating 
liberally  the  workmen  for  the  discovery  and  preservation  of 
them.  Dr.  Hofmann  arrived  at  the  spot  and  saw,  with  extreme 
pleasure,  the  indications  of  a  magnificent  specimen.  He 
directed  the  operations  of  the  men  so  that  they  worked  out  the 
block  without  injury  to  the  skeleton,  and  he  then  with  his  own 
hands  cleared  away,  by  degrees,  the  yielding  matrix,  exposing 
the  extraordinary  jaws  and  teeth,  which  have  been  the  subject 
of  so  many  drawings,  descriptions,  and  discussions.  This  fine 
specimen,  which  Hofmann  had  transported  with  so  much  satis- 
faction to  his  collection,  soon,  however,  became  a  source  of 
chagrin  to  him.  Dr.  Goddin,  one  of  the  canons  of  Maestricht, 
who  owned  the  surface  of  the  soil  beneath  which  was  the  quarry 
whence  the  fossil  had  been  obtained,  when  the  fame  of  the 
specimen  reached  his  ears,  pleaded  certain  feudal  rights  in  sup- 
port of  his  claim  to  it.  Hofmann  resisted,  and  the  canon  went 
to  law.  The  whole  chapter  supported  their  reverend  brother, 
and  the  decree  ultimately  went  against  the  poor  surgeon,  who 
lost  both  his  specimen  and  his  money,  for  he  was  made  to  pay 
the  costs  of  the  action.  The  Canon  Goddin,  leaving  all  remorse 
to  the  judges  who  had  pronounced  the  iniquitous  sentence,  be- 
came the  happy  and  contented  possessor  of  this  unique  example 
of  its  kind.  But  justice,  though  tardy,  comes  at  last.  When 
the  town  was  bombarded  by  the  French,  directions  were  given 
to  spare  the  suburb  where  the  famous  fossil  reposed.  After 
the  capitulation,  the  grenadiers  discovered,  seized,  and  bore  off 


EVOLUTION  AND  NATURE  STUDIES          411 

the  specimen  in  triumph  to  the  commissarial  residence.  The 
excellent  soldiers  always  knew  how  to  appreciate  and  respect 
the  monuments  of  art  and  science.  The  mosasaur  was  trans- 
planted and  still  remains  in  the  Museum  of  the  Garden  of 
Plants,  Paris,  and  is  the  subject  of  more  literature  than  any 
extinct  animal. 

Remains  of  the  mosasaurs  were  first  discovered  in  England 
in  1833,  at  Lewes.  In  America,  mosasaurs  were  first  found  in 
the  cretaceous  beds  at  Great  Bend,  Missouri,  about  the  year 
1820,  by  Major  O'Fallon,  Indian  agent.  He  found  a  fine  speci- 
men, and  took  it  to  his  home  in  St.  Louis.  Dr.  Goldfuss  first 
described  it  in  1843,  with  accompanying  plates,  the  skeleton 
having  been  taken  to  Germany  by  Prince  Maximilian.  He  de- 
fined the  parietal  and  jugal  arches,  pterygoids  and  vomers,  the 
position  of  the  quadrate,  and  the  presence  of  the  sclerotic 
plates.  Since  that  time  our  knowledge  of  the  mosasaurs  has 
been  largely  increased  by  the  explorations  and  efforts  of  Cope, 
Marsh,  Dollo,  Owen,  Leidy,  Williston,  Baur,  Merriam,  Gaudry, 
Gervais,  and  others.  Cope,  perhaps,  defined  the  largest  num- 
ber of  species.  March  defined  the  stapes,  columella,  transverse 
and  hyoid,  and  the  presence  of  hind  limbs.  Dollo  has  materi- 
ally increased  the  data  of  mosasaurs  and  has  added  four  new 
genera.  Baur  gave  the  first  complete  description  of  the  skull 
of  a  species  of  Platecarpus.  Williston  and  Case  first  described 
the  vertebral  column  and  extremities  and  the  general  form  of 
mosasaurs.  The  former  has  contributed  most  to  our  knowledge 
of  mosasaurs  in  the  Kansas  Cretaceous,  and  made  the  first  cor- 
rect restoration,  which  is  made  one  of  the  bases  of  this  paper. 

Professor  S.  W.  Williston,  University  of  Kansas,  because  of 
his  perfected  restorations  and  wide  studies  of  the  sea-serpent- 
like  saurians,  the  mosasaurs  and  other  marine  saurians,  must 
rank  as  the  highest  authority.  It  is  largely  on  his  material 
that  it  is  possible  to  present  something  like  a  complete  view  of 
the  gigantic  monsters  that  swam  the  Cretaceous  seas  and  gave 
origin  to  our  notions  of  mythical  sea-serpents.  Kansas  is  the 
great  center  of  the  Cretaceous  time  of  occupation,  and  it  is 
within  its  borders  that  the  largest  number  of  species  and  genera 
of  sea-serpents  have  been  discovered.  It  is  natural,  perhaps, 


412  ACHIEVEMENTS  IN  SCIENCE 

that,  living  in  the  vicinity  of  the  most  prolific  Cretaceous  re- 
mains, Professor  Williston  should  be  better  able  than  scientists 
more  remote  to  complete  our  knowledge  of  marine  saurians. 

There  are  three  groups  of  the  serpentlike  sea-saurians — the 
ichthyosaurs,  plesiosaurs,  and  mosasaurs.  Of  the  mosasaurs, 
Kansas  has  produced  the  largest  number  of  species,  twelve  of 
which  have  been  satisfactorily  described.  New  Jersey,  Ala- 
bama, Carolina,  and  Mississippi  have  perhaps  ten  valid  species. 
Dakota  has  favored  us  with  three  species.  It  is  estimated  that 
of  fifty  species  attributed  to  North  America,  about  twenty-five 
or  thirty  will  be  distinguished  as  distinct.  It  is  expected  that 
in  the  Fort  Pierre  formation  of  the  Dakota  region  other  species 
will  be  found,  as  it  has  been  but  imperfectly  explored.  Europe 
has  about  a  dozen  species,  and  New  Zealand  several  more. 
Probably  only  about  forty  species  of  twice  as  many  alleged  to 
have  been  discovered  in  the  world  will  stand  the  test  of  critical 
examination. 

Of  plesiosaurs,  America  has  produced  about  ten  and  the 
Old  World  many  more  species  that  will  stand.  Many  species 
of  ichthyosaurs  are  recorded  from  Europe,  India,  Africa,  Aus- 
tralia, New  Zealand,  and  the  arctic  regions,  and  one  or  two  in 
America,  the  toothless  Baptanodon  from  the  Jurassic  of  Wyo- 
ming being  the  type.  All  three  groups  had  paddles  with 
webbed  digits,  but  none  had  claws.  Williston  thinks  that  the 
ancestors  of  the  mosasaurs  were  land  lizards.  Dollo  thinks 
that  the  ancestors  were  the  peculiar  group  of  lizards  which 
appeared  in  the  commencement  of  the  Cretaceous  known  as 
Dolichosauria.  Baur  would  derive  the  mosasaurs  from  even 
more  specialized  lizards,  and  believes  that  their  relationship  is 
very  close  to  the  monitors  of  the  present  day. 

The  ichthyosaurs  are  thought  by  Cope  to  be  derived  from 
Homceosaurus  (beakless  lizards)  of  the  Jurassic;  and  these 
from  the  Palceohatteria  (ancient  hatteria),  a  rhynchocephalian 
(snout-head)  which  flourished  as  early  as  Permian  times ;  and 
these  from  the  Labitosaurust  an  ancestor  below  the  Carbonifer- 
ous in  the  Palaeozoic  Age ;  from  which  also  sprang  the  lizardlike 
saurians,  the  dimetrodons  (Otoccelius),  which  gave  origin  to  the 
turtles  (Testudinata).  Some  members  of  the  group  to  which 


I 


EVOLUTION  AND  NATURE  STUDIES          413 

the  plesiosaurs  belong  were  land  animals,  and  hence  the  origin 
of  the  whole  group  is  clearly  from  land  species.  It  is  not  now 
presumed  that  the  marine  saurians  had  much  power  of  progres- 
sion on  land,  but  they  may  have  climbed  on  to  the  beaches  to 
lay  their  eggs.  It  is  further  presumed  by  Morris  that  in  later 
times  the  eggs  of  saurians  were  devoured  by  other  animals, 
contributing  to  the  extinction  of  all  saurians. 

Three  species  of  representative  genera  of  Kansas  mosasaurs 
have  been  restored  by  Williston  from  material  in  the  University 
of  Kansas. 

Clidastes  velox  (Marsh)  is  a  typical  mosasaur,  the  perfected 
skeleton  of  which  is  twelve  feet  in  length.  Pumilus,  of  the 
same  genus,  is  given  as  six  feet  in  length,  which  would  rank  it 
as  perhaps  the  smallest  mosasaurian.  The  clidastes  of  Kansas 
had  short,  powerful  propelling  tails,  which  would  indicate  a 
lesser  speed  than  that  of  their  longer-tailed  contemporaries. 
The  clidastes  had  small  hind  limbs,  showing  further  deficiency 
in  speed.  The  animals  were  slender,  with  short  heads.  The 
vertebrae  were  firm,  closely  articulated  with  the  best  system  of 
interlocking  of  any  of  the  mosasaurs.  The  limbs  were  flexible 
and  strong,  with  closely  articulating  bones  and  fully  developed 
tarsus  and  carpus.  The  aggregate  of  these  characters  indi- 
cates the  most  snake-like  form  and  method  of  progression 
through  water  of  all  the  mosasaurs.  The  genus  Clidastes  was 
founded  by  Cope  in  1869,  but  may  ultimately  give  way  to  the 
genus  Mosasaurus  of  Conybeare.  Cope's  views  of  clidastes  con- 
clude that  the  animals  were  not  as  large  as  those  of  the  genus 
Liodon  (Owen),  but  more  elegant  and  flexible,  with  an  additional 
pair  of  articulations  at  either  end  of  each  vertebra — the  zygo- 
sphenes — to  prevent  dislocation  by  contortions.  A  larger  and 
still  more  elegant  species  was  Clidastes  tortor  (Cope),  with  lithe 
movements  which  enabled  it  to  capture  fish  by  means  of  its 
knife-shaped  teeth,  which  were  very  numerous.  Tortor  was 
very  slender,  with  a  long  and  lance-shaped  head.  It  was  up- 
ward of  twenty  feet  in  length,  with  a  head  two  feet  and  a  half 
long,  the  vertebral  column  elongate  and  the  head  narrow  and 
pointed. 

The  second-type  mosasaur  perfected  by  Williston  is  Plate- 


414  ACHIEVEMENTS  IN  SCIENCE 

carpus  coryphceus  (Cope).  Its  special  characteristics  are  a  short 
muzzle,  slender  vertebrae,  and  an  imperfect  interlocking  zygo- 
sphene.  The  hind  paddles  are  smaller  than  those  forward,  but 
thought  to  have  been  more  powerful  propelling  functions  than 
those  possessed  by  other  genera.  A  type  skeleton  measures 
fourteen  feet,  and  may  have  been  a  young  animal.  The  teeth 
were  very  curved  and  pointed,  and  formed  effective  weapons. 
The  neural  spines,  not  closely  connected,  indicate  flexibility. 
The  general  characters  suggest  a  powerful  predaceous  sea-ser- 
pent. The  genus  was  founded  by  Cope  in  1869;  it  has  a  wide 
distribution,  and  seven  or  eight  species  belong  to  it. 

Tylosaurus proriger  (Cope)  is  the  third  of  Williston's  type 
Kansas  specimens  perfected  in  restoration.  It  is  considered 
the  most  specialized  of  the  mosasaurs.  The  skeleton  in  hand 
is  twenty-three  feet  in  length,  and  shows  a  wholly  cartilaginous 
carpus  and  tarsus,  more  elongated  digits,  and  a  greater  number 
of  phalanges  than  possessed  by  any  other  genus,  the  result  of 
long  aquatic  habits.  The  hind  paddles  are  the  largest,  and  the 
fifth  digit  has  undergone  but  little  reduction,  indicating  charac- 
ters of  a  very  primitive  rank.  The  vertebrae  are  more  flexible 
than  in  other  genera,  but  they  are  relatively  smaller  and  not  at 
all  strong.  The  skull  is  more  elongated  anteriorly.  In  the 
same  genus  was  a  much  larger  species,  T.  dyspelor  (Cope), 
which  was  one  of  the  most  formidable  of  the  mosasaurs. 
Another  perfected  sea-serpent  of  terrible  powers  was  Mosasau- 
rus  honidus  (Williston),  which  had  a  ram  nose,  and  evidently 
battered  its  foes  when  it  could  get  at  them.  Williston's  per- 
fect skull  from  Dakota  enabled  him  to  correct  many  errors  in 
vogue.  The  new  genus  Brachysaurus,  formed  by  Williston, 
contains  one  species  denned  by  him — Overtoni,  from  Dakota. 
It  had  a  stout,  very  broad  head,  stout  jaws  and  teeth,  and  stout, 
broad  paddles.  In  appearance  it  suggests  a  terrible  fighter, 
unadapted  to  rapid  pursuit  or  flight. 

Williston  thinks  that  the  food  of  the  sea-serpent-like  sauri- 
ans  must  have  consisted  of  fishes  of  moderate  size,  with  occa- 
sional victims  of  their  own  kind.  He  says :  "  While  the  flexi- 
bility and  loose  union  of  the  jaws  undoubtedly  permitted  animals 
of  considerable  size  to  be  swallowed,  the  structure  of  the  thoracic 


EVOLUTION  AND  NATURE  STUDIES          415 

girdle  would  not  have  permitted  any  such  feats  of  deglutition 
of  which  the  python  and  boa  are  capable.  The  animals  must 
have  been  practically  helpless  on  land.  They  were  not  suffi- 
ciently serpentine  to  move  about  without  the  aid  of  limbs,  and 
these  were  not  at  all  fitted  for  land  locomotion.  They  lived  in ' 
open  seas,  often  remote  from  the  shores.  Their  pugnacity  is 
amply  indicated  by  the  many  scars  and  injuries  they  received, 
probably  from  others  of  their  own  kind." 

Over  the  water  were  the  flying  saurians  of  formidable  pro- 
portions, and  which  may  have  been  both  pursued  and  pursuer, 
according  to  size  of  mosasaur  and  pterosaur.  The  pterosaur 
had  a  wing  expanse  of  eighteen  to  nineteen  feet,  as  instanced 
in  Ornithostoma  umbrosum  (Cope),  the  largest  in  size,  and  O. 
ingens  (Marsh).  The  pterosaurs  flew  with  leathery  wings  over 
the  waves,  plunging  to  seize  unwary  fishes  or  perhaps  to  be 
seized  by  mosasaurs,  or  soaring  at  a  safe  distance  while  watch- 
ing the  combats  of  swimming  saurians.  At  nightfall  they 
trooped  along  the  shores,  at  last  to  suspend  themselves  to  the 
cliffs  by  the  claws  of  their  wing  limbs. 

Prof.  O.  C.  Marsh,  of  Yale  College,  was  the  first  naturalist 
to  discover  sufficient  of  the  missing  parts  of  skeletons  to  deter- 
mine that  marine  saurians  propelled  themselves  with  paddles 
rather  than  flippers.  As  to  the  scales  and  skin  found  perfectly 
preserved  by  Snow,  they  do  not  differ  materially  from  those  of 
the  Old  World  lizards,  the  monitors,  existing  toilay.  The  pad- 
dles, skin,  and  scales  are  very  delicate  functions,  and  it  is  re- 
markable that  they  should  have  been  preserved  through  mil- 
lions of  years.  Williston  says  of  the  paddles:  "The  specimen 
figured  by  Chancellor  F.  H.  Snow,  of  the  University  of  Kansas, 
has  been  thoroughly  cleaned  from  the  matrix,  enabling  an  accu- 
rate drawing  to  be  made,  also  a  photographic  reproduction  as 
it  lies  on  a  chalk  slab.  The  parts  concealed  beneath  the  ribs 
and  vertebrae  have  been  carefully  laid  bare  from  the  opposite 
side  and  their  position  shown.  The  position  of  the  paddle  is  a 
natural  one,  and  the  fact  is  of  interest  as  showing  the  general 
expansion  and  curvature  of  the  digits."  The  limb  is  very  flexi- 
ble, with  considerable  space  between  the  bones,  which  were 
but  partly  filled  out  with  cartilage,  and  must  have  had  very  free 


416  ACHIEVEMENTS  IN  SCIENCE 

articulations.  The  remains  of  the  skin  were  found  between 
the  bones,  indicating  a  thin,  pliable  membrane,  and  extending 
fully  between  the  fingers  to  their  tips.  Small  scute-like  scales 
extended  as  far  as  the  metacarpals.  The  fifth  finger  is  long. 
The  paddles  are  slenderer,  more  flexible,  and  relatively  longer 
than  in  other  genera,  which,  with  other  characteristics,  would 
show  that  Tylosaurus  was  the  least  lizard-like  of  the  Pythono- 
morpha  (Cope.)  As  to  the  structure  of  the  hind  paddle,  it  is 
of  interest  in  having  five  functional  toes,  although  Williston 
thinks  that  the  fifth  toe  was  undergoing  reduction,  and  that  the 
first  toe  was  not  as  long  as  in  the  front  paddle.  He  concedes 
five  toes  to  the  hind  paddle  of  Platecarpus  (Cope),  but  doubts, 
in  the  absence  of  a  complete  skeleton,  if  Clidastes  had  more 
than  four  functional  toes,  as  in  Mosasaurus.  Upon  this  char- 
acter, together  with  the  absence  of  a  sternum,  he  has  estab- 
lished two  families,  Tylosauridce  and  Mosasaurid&  and  the  two 
typical  genera,  representing  the  extremes  of  development  of 
this  order  of  reptiles. 

In  this  connection  it  is  interesting  to  note  the  views  of  cer- 
tain scientific  men  of  the  times  in  which  these  gigantic  sea-ser- 
pents existed. 

The  views  of  Prof.  Frank  C.  Baker,  curator  of  the  Chicago 
Academy  of  Sciences,  follow :  "At  the  time  the  great  sea- 
lizards  lived,  North  America  was  shaped  something  like  the 
following :  It  included  all  of  Northeastern  Canada  and  Nova 
Scotia ;  the  shore  line  was  the  same  as  at  present  as  far  as  New 
York,  where  it  was  deflected  to  the  southwest  and  went  through 
the  western  part  of  New  J  ersey,  Delaware  and  Maryland,  and 
then  went  directly  across  the  middle  of  Alabama,  north  again 
to  the  mouth  of  the  Ohio  River  where  it  meets  the  Mississippi 
River,  then  north  into  Iowa,  and  finally  north  and  northwest 
across  the  United  States  and  British  America.  Herein  existed 
a  great  inland  sea  in  which  the  sea-lizards  lived.  The  past  his- 
tory of  the  world  tells  us  that  thousands  of  animals  of  gigantic 
size  lived  in  the  ancient  seas.  In  old  Jurassic  and  Cretaceous 
times  we  had  such  queer  combinations  as  Ichthyosaurus  (or  fish 
lizard)  and  Plesiosaurus.  Not  only  were  reptiles  found  in  the 
water;  they  flew  about  in  air.  The  latter  were  represented  by 


EVOLUTION  AND  NATURE  STUDIES          417 

the  Rhamphorynchus,  a  bird-like  reptile  which  had  wings  like  a 
bat,  teeth  like  an  alligator,  and  the  tail  of  a  lizard.  In  the  Con- 
necticut Valley  we  find  the  footprints  of  huge  reptiles  in  the  red 
sandstones  whose  feet  measured  from  those  of  a  few  inches  in 
length  to  the  footprints  of  the  gigantic  Otozoum,  which  meas- 
ured twenty-two  inches  in  length,  having  a  step  of  some  five 
feet." 

An  immense  amount  of  literature  has  been  printed  on  the 
subject  of  the  Cretaceous  formation  and  its  inhabitants.  Very 
recently  there  have  been  immense  advances  made  in  the  resto- 
ration of  species  existing  in  Cretaceous  times.  This  article, 
therefore,  is  in  the  nature  of  scientific  news,  and  a  separation 
of  facts  from  a  mass  of  errors.  In  looking  over  the  works  of 
others,  one  is  impressed  by  the  many  mistakes  made  by  spe- 
cialists, owing  to  imperfect  skeletons  and  collections.  A  care- 
ful study  of  these  errors  has  been  made  in  the  light  of  the  latest 
skeletons  reconstructed  and  the  latest  discoveries  made. 

The  Kansas  University,  in  securing  three  perfect  type  spec- 
imens of  three  genera  of  mosasaurs,  presents  three  important 
items  of  scientific  news.  These  skeletons  teach  us  the  errors 
and  pitfalls  into  which  specialists  have  fallen  who  lacked  certain 
parts  of  the  skeletons  and  filled  out  the  gaps  by  aid  of  the 
imagination.  Only  recently  the  country  was  startled  by  the 
alleged  discovery  of  the  skeleton  of  a  supposed  reptile,  having 
a  length  of  two  hundred  and  fifty  feet.  The  newspapers  gave 
startling  pictures  of  the  supposed  appearance  of  this  reptile 
while,  on  earth.  Professor  Williston  naturally  wanted  to  see 
this  gigantic  animal,  the  largest  ever  discovered.  On  examina- 
tion of  its  bones  he  saw  at  once  that  it  was  a  whale.  It  can 
safely  be  asserted  that  no  animal  ever  attained  a  length  of  two 
hundred  and  fifty  feet.  Perhaps  as  serious  errors  as  this  may 
be  found  in  many  of  our  text-books  and  monographs,  due,  of 
course,  to  former  incomplete  skeletons.  The  appearances  of 
the  skulls,  the  jaws,  and  the  teeth  have  been  painfully  distorted 
in  like  publications  and  on  charts  in  class  rooms,  and  demand 
a  thorough  overhauling  before  our  youth  are  further  taught 
errors.  With  late  complete  discoveries,  we  have  now  exact 
appearances  of  the  functions  of  the  heads  from  which  we  can 
27 


418  ACHIEVEMENTS  IN  SCIENCE 

derive  correct  views.  It  was  formerly  thought  that  the  eyes 
of  the  mosasaurs  were  directed  upwardly ;  to-day  it  is  known 
that  they  were  directed  laterally,  as  in  living  lizards.  It  has 
been  supposed  that  mosasaurs  attained  a  length  of  one  hundred 
feet ;  no  skeleton  has  been  found  which  would  show  a  length 
of  more  than  fifty  feet.  The  great  majority  of  skeletons  taken 
range  from  sixteen  to  twenty  feet  in  length.  It  was  formerly 
supposed  that  mosasaurs  had  the  powers  of  running,  springing, 
and  climbing  on  land ;  it  is  now  known  that  they  were  wholly 
confined  to  salt  water,  and  merely  climbed  the  beaches  in  order 
to  lay  eggs.  It  is  not  an  easy  step  from  mosasaurs  to  modern 
snakes ;  it  is  an  utter  impossibility.  Professor  Marsh  formerly 
thought,  and  it  has  been  taught  in  the  class  rooms,  that  the 
bodies  of  mosasaurs  had  bony  scales ;  they  had  skins,  and  were 
scaled  throughout  like  modern  lizards  and  snakes.  The  Rham- 
phorynchus  has  been  held  up  to  us  as  a  "  lizard-like  bird  " ;  it 
was  no  more  like  a  bird  than  is  a  bat ;  it  was  a  bird-like  reptile. 
These  suggestions  certainly  point  to  the  necessity  of  a  revision 
of  the  text-books  and  charts  in  use  in  class  rooms,  which  in 
many  instances  should  become  obsolete  because  of  perfected 
restorations. 

Specialists  regard  the  marine  saurians  as  having  existed 
some  millions  of  years  ago.  They  conclude  that  these  animals 
had  at  least  a  million  years  of  existence  in  various  forms. 
While  it  may  be  venturing  into  the  domain  of  the  encyclopaedia 
to  state  the  causes  of  these  conclusions,  a  word  here  may  not 
be  out  of  place.  The  Cretaceous  formation,  in  which  the  marine 
saurians  are  found,  is  of  chalk,  green  sands,  etc.,  and  ranges  in 
thickness  from  10,000  to  20,000  feet  or  more  It  existed  in 
the  last  part  of  the  Mesozoic  realm.  From  the  thickness  and 
position  in  geological  strata  scientists  deduce  its  age  and  place 
in  Nature.  As  the  remains  of  marine  saurians  are  found  only 
in  the  Cretaceous  deposits,  specialists  speak  of  them  as  existing 
several  million  years  ago.  At  that  time  were  numerous  fishes, 
birds,  reptiles,  and  plants. 


BIOGRAPHIES 


JEAN  Louis  RUDOLPHE  AGASSIZ,  naturalist,  was  born  in  Motier,  Switzer- 
land, May  28,  1807.  In  boyhood  his  interest  in  books  was  small,  but  his 
fondness  for  objects  of  natural  history  and  domestic  pets  correspondingly  large. 
He  studied  for  four  years  at  the  college  for  boys  at  Bienne,  and  here,  aside 
from  his  studies,  made  his  first  collection  of  fishes.  He  progressed  to  the 
college  at  Lausanne,  thence  to  the  medical  school  at  Zurich,  from  which  insti- 
tution he  went  to  Heidelberg,  where  he  studied  botany  and  anatomy,  and, 
in  1827,  went  to  Munich,  where  he  lodged  in  the  house  of  Dr.  Johann  Dollinger, 
who  encouraged  him  in  his  predilection  for  zoology.  His  work  on  "Fossil 
Fishes,"  published  in  1830,  gave  him  a  place  among  European  scientists,  and 
the  next  year  he  went  to  Paris  and  enlisted  the  interest  of  Cuvier,  with  whom 
he  stayed  until  the  latter's  death.  He  sided  with  Cuvier  in  his  opposition  to 
the  development  theory  advanced  by  Geoffrey.  Through  the  interest  of  Hum- 
boldt,  he  obtained  the  chair  of  natural  history  in  the  college  at  NeufchHtel  in 
1832.  The  next  year  he  published  the  first  of  his  five  quarto  volumes,  "  Re- 
cherches  sur  les  Poissons  Fossiles, "  the  last  volume  coming  ten  years  later. 
He  made  excursions  to  the  Jura  and  the  Alps  to  study  glaciers,  had  a  station 
built  on  the  center  of  the  Aar  glacier  twelve  miles  from  any  human  abode,  and, 
in  1840,  published  "  Etudes  sur  les  Glaciers,"  followed  in  1847  by  his  "  Systeme 
Glaciers."  Investigations  of  fossil  remains  occupied  him  until  1846,  when  he 
visited  America  to  study  its  natural  history  and  geology.  His  lectures  in  the 
large  eastern  cities  gave  him  a  great  popularity  ;  the  richness  of  the  American 
field  for  a  naturalist  decided  him  to  remain  here,  and,  in  1848,  he  accepted  the 
chair  of  zoology  and  botany  at  the  Lawrence  Scientific  School  of  Harvard  Uni- 
versity. Though  invited  to  return  to  Europe  and  occupy  chairs  in  various 
universities,  he  remained  in  his  adopted  country,  being  instrumental  in  the 
founding  of  the  Museum  of  Comparative  Zoology  at  Harvard,  known  more 
popularly  as  the  Agassiz  Museum,  and  the  Andersen  School  of  Natural  His- 
tory on  Buzzard's  Bay.  Among  his  works  written  in  English  are  "  Principles 
of  Zoology,"  "  The  Structure  of  Animal  Life,"  and  "  Scientific  Results  of  a 
Journey  in  Brazil."  He  died  in  Cambridge,  December  14,  1873. 

RAY  STANNARD  BAKER,  magazine  writer  and  editor,  was  born  in  Lansing, 
Mich.,  April  17,  1870.  In  1892  he  began  writing  stories  for  the  "Youth's 
Companion"  and  articles  for  "The  Outlook,"  "  Independent,"  and  "Har- 
pers' Weekly. "  In  1898  he  became  a  member  of  the  staff  of  the  S.  S.  McClure 
Company,  being  occupied  at  times  on  both  newspaper  syndicate  and  magazine. 

419 


420  ACHIEVEMENTS  IN  SCIENCE 

In  1899  he  went  to  Cuba,  in  1900  to  Europe  in  the  interests  of  the  McClure  es- 
tablishments, and  in  1901  to  Arizona,  New  Mexico,  and  California  for  the 
Century  Company.  He  published  the  "  Boys'  Book  of  Inventions"  in  1899, 
"  Our  New  Prosperity"  in  1900,  and  "  Seen  in  Germany"  in  1901. 

SIR  ROBERT  BALL,  English  astronomer,  was  born  in  Dublin,  July  i,  1840. 
He  was  appointed  Lord  Ross's  astronomer  in  1865,  and,  in  1873,  became 
Professor  of  Mathematics  and  Mechanics  at  the  Royal  Irish  College  of  Science. 
At  present  he  is  Lowndean  Professor  of  Astronomy  and  Geometry,  Cambridge. 
He  is  the  author  of  "The  Story  of  the  Heavens,"  "Starland,"  etc.,  and  is 
well  known  in  America  as  a  lecturer  on  astronomical  subjects. 

PIERRE  EUGENE  MARCELLIN  BERTHELOT,  a  French  chemist,  was  born  in 
Paris,  October  25.  1827.  In  1859  he  became  Professor  of  Organic  Chemistry 
in  the  Ecole  de  Pharmacie,  and  in  1865  assumed  the  same  position  in  the  Col- 
lege de  France.  In  1876  he  was  made  Inspector-General  of  Higher  Educa- 
tion, and  in  1886  Minister  of  Public  Instruction.  He  won  great  distinction 
by  the  synthesis  of  organic  compounds  formerly  supposed  to  result  only  from 
the  action  of  vital  forces.  He  published  "  La  Synthese  Chimique  "  and  many 
other  scientific  works. 

FRANK  MICHLER  CHAPMAN,  zoologist,  was  born  June  12,  1864,  in  Engle- 
wood,  New  Jersey.  In  1887  he  was  appointed  Assistant-Curator  of  Verte- 
brate Zoology  in  the  American  Museum  of  Natural  History,  which  position  he 
continues  to  hold.  He  is  President  of  the  Linnrean  Society  of  New  York,  and 
has  been  a  member  of  the  American  Ornithologists'  Union  since  1888.  He  has 
written  "Handbook  of  Birds  of  Eastern  North  America,"  "Bird-Life,"  and 
"  Bird  Studies  with  a  Camera." 

HENRY  DRUMMOND,  Scotch  scientist  and  religious  writer,  was  born  at 
Stirling,  Scotland,  on  August  17,  1851.  He  acquired  his  education  at  the 
universities  of  Edinburgh  and  Tubingen,  and  at  the  Free  Church  Divinity 
Hall,  where  he  pursued  the  courses  in  theology.  After  being  ordained  he  was 
appointed  to  a  mission  chapel  at  Malta ;  but  he  abandoned  the  work  of  the 
ministry,  and,  in  1887,  became  Professor  of  Natural  Science  in  the  Free  Church 
College,  Glasgow.  The  intervals  between  his  professorial  occupations  were  spent 
in  travel,  with  scientific  investigations  as  a  partial  objective.  He  visited  South 
Africa  and  the  Rocky  Mountains  with  this  end  in  view,  and  made  lecture  tours 
in  Australia,  Canada,  and  the  United  States.  In  1883  he  published  "  Natural 
Law  in  the  Spiritual  World, "  which  was  followed  later  by  "  The  Ascent  of 
Man,"  two  works  in  which  he  has  endeavored  to  bring  modern  scientific 
methods  to  the  discussion  of  the  phenomena  of  the  immaterial  universe.  In 
1888  he  published  his  book  on  "  Tropical  Africa."  Besides  the  foregoing  he 
is  the  author  of  "  Pax  Vobiscum,"  and  "  The  Greatest  Thing  in  the  World, " 
published  in  1890,  and  "  The  Programme  of  Christianity,"  in  1892.  He  died 
in  Tunbridge  Wells,  England,  March  n,  1897. 


BIOGRAPHIES  421 

MICHAEL  FARADAY,  chemist  and  physicist,  was  born  in  Newington  Butts, 
September  22,  1791.  His  father  was  a  poor  blacksmith  with  a  large  family. 
Michael  was  early  apprenticed  to  a  bookbinder  and  stationer,  with  whom  he 
remained  eight  years.  As  a  boy  he  was  interested  in  science  and  made  experi- 
ments. In  1812,  after  attending  lectures  given  by  Sir  Humphrey  Davy  at  the 
Royal  Institution,  he  sent  his  notes  to  the  lecturer  and  sought  his  aid  to  escape 
from  trade.  Davy  engaged  him  as  assistant  in  the  laboratory  at  the  Royal  In- 
stitution, and  in  1813  took  him  on  his  journey  in  France,  Switzerland,  Italy 
and  the  Tyrol.  On  their  return,  Faraday  reentered  the  services  of  the  Royal 
Institution.  In  1825  he  was  elected  a  Fellow  of  the  Royal  Society  and  in  1830 
began  to  contribute  to  it  accounts  of  his  discoveries  in  magnetism  and  electric- 
ity. In  1835  he  was  appointed  Professor  of  Chemistry  to  the  Royal  Institu- 
tion, where  he  delivered  the  annual  lectures  until  his  death,  His  investigations 
tended  to  establish  the  theory  that  electricity,  light,  and  heat  are  modifications 
of  the  same  force  and  convertible  into  one  another.  In  1835  his  services 
obtained  from  the  State  a  pension  of  ^300  a  year,  and  in  1846  the  Rumford 
and  Royal  Medals  were  awarded  him  for  the  discovery  of  diamagnetism.  His 
volumes  of  "  Experimental  Researches"  were  published  at  intervals  from  1839 
to  1859.  His  nature  was  deeply  religious  and  his  manner  simple  and  unaf- 
fected. It  was  his  custom  to  give  lectures  at  the  Royal  Institution  at  Christ- 
mas to  an  audience  of  children.  The  last  of  such  courses  was  on  "The 
Chemical  History  of  a  Candle,"  in  1861.  In  1858  the  Queen  assigned  him  a 
residence  at  Hampton  Court,  where  he  died  August  25,  1867. 

CAMILLE  FLAMMARION,  French  astronomer,  was  born  in  Montigny-le-Roi, 
February  25,  1842.  He  is  the  author  of  popular  works  on  astronomy,  many 
of  which  have  been  translated  into  English.  Among  them  are  "  The  Stars," 
"The  World  Before  the  Creation,"  "Uranus,"  "Comets,"  and  "Popular 
Astronomy." 

AUSTIN  FLINT,  American  physician,  writer  on  medicine,  was  born  in 
Petersham,  Mass,  in  1812.  He  graduated  with  the  degree  of  M.D.  at  Har- 
vard in  1833.  He  was  one  of  the  founders  of  the  Buffalo,  N.  Y.,  Medical 
College  in  1847,  and  in  1861  was  appointed  Professor  of  the  Principles  and 
Practice  of  Medicine  in  Bellevue  College  Hospital,  New  York,  and  Professor 
of  Pathology  and  Practical  Medicine  in  the  Long  Island  College  Hospital. 
He  published  "  Practical  Treatise  on  Diseases  of  the  Heart,"  "  The  Practice 
of  Medicine,"  "Auscultation  and  Percussion,"  and  "Clinical  Medicine." 

AGNES  GIBERNE,  English  author,  was  born  at  Ahmednugger,  India.  She 
began  to  write  at  seven  years  of  age,  her  first  story  for  children  being  published 
when  she  was  only  seventeen.  Her  most  popular  work  has  been  her  scientific 
writings,  "  Sun,  Moon  and  Stars,"  "  The  Starry  Skies,"  "  Among  the  Stars," 
"The  Ocean  of  Air,"  "  The  World's  Foundations,"  "Radiant  Suns,"  etc. 
She  lives  at  Eastbourne,  England. 


422  ACHIEVEMENTS  IN  SCIENCE 

ELISHA  GRAY,  electrician  and  inventor,  was  born  near  Barnesville,  Ohio, 
August  2,  1835.  Early  in  life  he  learned  blacksmithing,  carpentry  and  boat- 
building, from  which  he  turned  to  pursue  special  studies  in  physical  science  at 
Oberlin  College,  where  he  constructed  the  apparatus  used  in  the  class  room  for 
experiments,  at  the  same  time  supporting  himself  by  working  at  his  trade.  In 
1867  he  invented  a  self-adjusting  telegraph  relay,  and  in  1869  established  a 
manufactory  of  electrical  apparatus  at  Cleveland,  Ohio.  He  perfected  the  type- 
writing telegraph,  the  telegraph  repeater,  telegraphic  switch,  annunciator,  etc. 
In  1872  he  organized  the  Western  Electric  Manufacturing  Company,  but  retired 
from  it  in  1874.  In  1876  he  invented  the  speaking  telephone  and,  in  the  dozen 
years  following,  took  out  more  than  fifty  patents  on  details  of  telephony.  In 
1893  he  invented  the  telautograph.  He  established  the  Gray  Electric  Company 
at  Highland  Park,  111.,  and,  in  1893,  organized  the  Congress  of  Electricians  in 
connection  with  the  World's  Columbian  Exposition,  and  was  made  its  chair- 
man. During  the  last  year  of  his  life  he  worked  upon  a  system  of  submarine 
signaling.  He  was  the  author  of  "  Experimental  Researches  in  Electro-Har- 
monic Telegraphy  and  Telephony,"  and  also  of  "Nature's  Miracles."  He 
died  in  Newtonville,  Mass.,  December  31,  1900. 

THOMAS  HENRY  HUXLEY,  English  biologist,  was  born  at  Ealing,  Middle- 
sex, England,  May  4,  1825.  He  studied  medicine  at  Charing  Cross  Hos- 
pital, and  in  i846-'so  went  as  Assistant- Surgeon  of  H.M.S.  "  Rattlesnake," 
which  made  an  expedition  to  explore  the  passage  between  the  Barrier  Reef  and 
the  Australian  coast.  His  studies  of  marine  life  were  afterwards  utilized  in  the 
preparation  of  many  scientific  papers  that  brought  him  high  honors.  He  be- 
came a  writer  and  lecturer  of  singular  force  and  clearness,  holding  a  professor- 
ship of  Natural  History  in  the  Royal  School  of  Mines,  with  a  curatorship  in 
the  Museum  of  Practical  Geology.  Among  his  more  popular  works  are  "  Man's 
Place  in  Nature,"  "Lay  Sermons,"  "Critiques  and  Addresses,"  "American 
Addresses,"  "Physiography,"  "Science  and  Culture,"  and  "Lessons  in 
Elementary  Physiology."  He  died  in  Eastbourne,  June  29,  1895. 

SIR  JOHN  LUBBOCK,  English  naturalist  and  statesman,  was  born  in  Lon- 
don, April  20,  1834.  He  went  to  school  at  Eton,  but  his  father  needed  his 
assistance  in  his  banking  house  and  he  entered  there  at  the  age  of  fourteen, 
becoming  a  partner  in  1856.  In  banking  affairs  he  has  introduced  such  improv- 
ing innovations  as  the  "  Country  Clearing  "  and  the  publication  of  the  Clearing 
House  returns.  He  was  chosen  Honorary  Secretary  to  the  Association  of 
London  Bankers,  and,  later,  became  the  first  President  of  the  Institute  of 
Bankers.  He  has  also  taken  an  active  interest  in  many  public  affairs,  has  been 
a  Member  of  Parliament  and  of  various  educational  boards,  President  of  the 
Royal  Society  and  of  the  British  Association  for  the  Advancement  of  Science, 
and  a  member  of  many  other  learned  bodies.  Among  his  works  may  be  men- 
tioned ' '  Prehistoric  Times,  as  Illustrated  by  Ancient  Remains  and  the  Man- 
ners and  Customs  of  Modern  Savages,"  "  The  Origin  of  Civilization  and  the 
Primitive  Condition  of  Man,"  "  The  Origin  and  Metamorphosis  of  Insects.' 


BIOGRAPHIES  423 

«  Ants,  Bees  and  Wasps,"  "On  the  Senses,  Instincts  and  Intelligences  of 
Animals,  with  Special  Reference  to  Insects,"  "  On  British  Wild-flowers  Con- 
sidered in  Relation  to  Insects,"  "  Flowers,  Fruits  and  Leaves."  In  the  field 
of  the  moral  and  aesthetic  he  has  written  "The  Pleasures  of  Life,"  "The 
Beauties  of  Nature,"  and  "  The  Use  of  Life."  In  1886  he  delivered  an  ad- 
dress before  the  London  Working  Men's  College  on  "  Books  and  Reading." 
When  it  was  published  in  1887  as  a  chapter  in  his  ' '  Pleasures  of  Life,"  it  had 
appended  a  list  of  the  one  hundred  best  books.  This  list  stands  high  in  the 
opinion  of  critics  and  is  often  quoted  or  referred  to.  He  lives  in  London  and 
in  High  Elms,  Down,  Kent. 

MAURICE  MAETERLINCK,  dramatist  and  man  of  letters,  was  born  in  Flan- 
ders in  1854.  All  his  school  life  was  spent  at  a  Jesuit  college,  where  he  was 
subject  to  severe  monastic  discipline,  modified,  however,  in  some  degree  by  his 
being  a  day  pupil,  He  began  writing  as  a  school-boy  and  persisted  in  this 
career  contrary  to  the  intentions  of  his  parents,  who  wished  him  to  be  a  bar- 
rister. He  read  French,  German,  and  English,  his  enthusiasm  in  the  latter 
field  being  for  Shakespeare  and  other  Elizabethan  dramatists,  for  Carlyle  and 
Emerson,  Rossetti  and  Swinburne.  He  made  a  profound  study  of  the  mysti- 
cal writers,  his  attention  being  drawn  to  them  by  the  discovery  in  the  public 
library  of  Brussels  of  the  ancient  and  curious  Flemish  manuscripts  of  Ruys- 
broeck.  His  work  is  of  the  Symbolist  order  and  he  is  looked  upon  as  the 
leader  of  a  movement  known  as  "  Young  Belgium."  He  began  publishing  in 
1890  by  issuing  a  volume  of  verse  entitled  "  Hot-House  Blooms,"  and  the  two 
dramas,  "The  Blind,"  and  "Princess  Maleine."  Other  dramas  followed: 
"The  Seven  Princesses,"  "  Pelleas  and  Melisande,"  "Alladine  and  Palo- 
mides,"  "  Aglavaine  and  Selysette,"  and  "  The  Intruder."  In  1897  appeared 
a  volume  of  essays  or  reflective  studies  grouped  around  a  central  theme  and 
called  "  The  Treasure  of  the  Humble."  It  was  followed  the  next  year  by  a 
similar  work,  "Wisdom  and  Destiny."  In  1901  appeared  a  nature  study: 
"  The  Life  of  the  Bee." 

ALEXANDER  G.  McAoiE,  an  American  meteorologist,  was  born  August  4, 
1863,  in  New  York  city.  He  graduated  from  the  College  of  the  City  of  New 
York  in  1881,  then  took  a  post-graduate  course  in  Harvard,  1882-85.  He 
was  in  the  physical  laboratory  of  the  United  States  Signal  Office  from  1886-37, 
was  appointed  to  the  United  States  Signal  Service,  Washington,  in  1891, 
where  he  remained  four  years,  and  then  became  local  forecast  official  in  New 
Orleans.  In  1899  he  accepted  a  simila*  position  at  San  Francisco,  where  he 
now  is.  He  has  written  extensively  on  meteorological  subjects. 

IRA  REMSEN,  Professor  of  Chemistry,  and  President,  since  June,  1901,  of 
Johns  Hopkins  University,  was  born  in  New  York,  February  10,  1846.  He 
graduated  from  the  College  of  the  City  of  New  York  in  1865,  after  which  he 
studied  medicine  at  the  College  of  Physicians  and  Surgeons  and,  later,  at  the 
University  of  Gottingen,  Germany,  where  he  took  the  degree  of  Ph.  D.  From 


424  ACHIEVEMENTS  IN  SCIENCE 

1872  to  1876  he  was  Professor  of  Chemistry  in  Williams  College,  at  which 
latter  date  he  took  the  Chair  of  Chemistry  in  Johns  Hopkins.  In  1879  ne 
founded,  and  has  ever  since  edited,  the  "  American  Chemical  Journal. "  He  has 
written  a  number  of  text-books  on  chemistry.  His  home  is  in  Baltimore,  Md. 

JOHN  TIMES,  collector  and  writer  of  curious  information,  was  born  at 
Clerkenwell,  England,  August  17,  1801.  He  was  educated  at  a  private  school 
at  Hemel,  Hempstead,  after  which  he  was  apprenticed  to  a  printer  and  drug- 
gist at  Dorking.  While  here  he  began  to  write,  and  his  first  contributions  ap- 
peared in  the  "  Monthly  Magazine"  in  1820.  He  went  to  London  to  serve  as 
amanuensis  to  Sir  Richard  Phillips,  and  at  the  same  time  began  his  contribu- 
tions to  London  periodicals,  but  chiefly  to  the  "  Mirror  of  Literature,"  which 
he  edited  from  1827  to  1838.  During  1839  and  1840  he  edited  the  "  Literary 
World,  "and  was  connected  with  the  "Illustrated  London  News,"  as  sub-editor 
under  Dr.  Charles  Mackay  from  1842  to  1858.  He  was  the  author  of  such 
works  as  "  Curiosities  of  London  ";  "  Anecdote  Biography  "  ;  Clubs  and  Club 
Life  in  London";  "Historic  Ninepins:  A  Book  of  Curiosities,  where  Old 
and  Young  May  Read  Strange  Matters  "  ;  "A  History  of  Wonderful  Inven- 
tions"; "Knowledge  for  the  People;  or  the  Plain  Why  and  Because"; 
"Lives  of  Wits  and  Humorists";  "Nooks  and  Corners  of  English  Life"; 
"  Past  and  Present " ;  "  Popular  Errors  Explained  and  Illustrated  " ;  "  Things 
Not  Generally  Known,  Familiarly  Explained";  "Walks  and  Talks  about 
London  ";  "  Wonderful  Inventions,  from  the  Mariner's  Compass  to  the  Elec- 
tric Telegraph. "  These  are  but  a  few  of  the  more  than  one  hundred  and  fifty 
titles  of  his  books,  consisting  of  compilations  of  interesting  facts  gathered 
from  every  conceivable  quarter  and  relating  to  the  most  varied  subjects.  He 
was  elected  Fellow  of  the  Society  of  Antiquarians  in  1854.  He  died  in  Lon- 
don March  6,  1875. 

JOHN  TROWBRIDGE,  an  American  physicist,  was  born  in  Boston,  Mass., 
in  1843.  He  was  educated  at  the  Boston  Latin  School  and  in  the  scientific 
department  of  Harvard  College.  In  1879  he  became  Professor  of  Experi- 
mental Physics  at  Harvard  and  has  won  special  distinction  as  an  electrician. 
Among  his  works  is  "  The  New  Physics." 

JOHN  TYNDALL,  English  physicist,  was  born  in  Leighlin-Bridge,  County 
Carlow,  Ireland,  August  21,  1820.  He  began  his  original  scientific  researches 
in  1847,  when  teacher  of  physics  in  Queenwood  College.  In  1853  he  was 
made  professor  in  the  Royal  Institution,  and  three  years  later  he  and  Prof. 
Huxley  visited  the  Alps  together,  and  wrote  a  work  on  the  structure  and  na- 
ture of  glaciers.  His  inquiries  and  experiments  in  connection  with  light,  heat, 
sound,  and  electricity  have  all  had  practical  results.  He  devoted  the  proceeds 
of  a  lecturing  tour  in  this  country  to  founding  scholarships  at  Harvard  and 
Columbia  Universities  for  students  devoting  themselves  to  original  research. 
Among  his  books  are  "  Glaciers  of  the  Alps,"  "  Mountaineering,"  "  Heat  as  a 
Mode  of  Motion,"  "On  Radiation,"  "Hours  of  Exercise  in  the  Alps," 


BIOGRAPHIES  425 

"  Fragments  of  Science,"  "  The  Floating  Matter  of  the  Air,"  and  volumes  on 
Light,  Sound,  Electricity,  and  the  forms  of  water.     He  died  December  4,  1893. 

ALFRED  RUSSEL  WALLACE,  English  naturalist  and  traveler,  was  born  in 
Usk,  Monmouthshire,  Scotland,  January  8,  1823,  was  educated  as  land  sur- 
veyor and  architect,  but  afterwards  devoted  himself  entirely  to  natural  history. 
He  explored  the  Valley  of  the  Amazon  and  Rio  Negro,  1848-52,  and  traveled 
in  the  Malay  Archipelago  and  Papua,  1854-62,  publishing  the  results  of  his 
explorations.  He  also  wrote  "  Contributions  to  the  Theory  of  Natural  Selec- 
tion," "Miracles  and  Modern  Spiritualism,"  "Geographical  Distribution  of 
Animals,"  "  Tropical  Nature,"  "  Island  Life,"  etc.  His  attention  is  occupied 
with  natural  history,  social  science,  and  scientific  literature.  He  is  President 
of  the  Land  Nationalization  Society. 

CHARLES  B.  WARRING,  American  scientist,  was  born  in  Charlton,  N.  Y., 
January  15,  1825.  He  graduated  from  Union  College  in  1845  ;  was  principal 
of  the  Collegiate  School  in  Poughkeepsie,  N.  Y.,  from  1857  to  1862,  and  in 
1863  established  the  Military  Institute  at  Poughkeepsie,  which  he  conducted 
until  1891.  Among  his  works  are  "  The  Mosaic  Account  of  Creation,  the 
Miracle  of  To-day  "  ;  "  Genesis  I.  and  Modern  Science." 


14  DAY  USE 

RETURN  TO  DESK  FROM  WHICH  BORROWED 
LOAN  DEPT. 

This  book  is  due  on  the  last  date  stamped  below,  or 

on  the  date  to  which  renewed. 
Renewed  books  are  subject  to  immediate  recall. 


~hn'59«" 

REcFb\D 

''JAN  14  1959 

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REC'D  LD 

MAR  1    19fi? 

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